move roles, files and templates dirs out of playbook dir into root dir

Because of how Ansible local relative search paths work, the global
"files" and "templates" directories need to be next to the playbooks.
However its not intuitive to look into the "playbooks" directory to find
the files and templates for a host.
Therefore move them out of the "playbooks" directory into the root
directory and add symlinks so everything still works.

Similarly for local roles, they also need to be next to the playbooks.
So for a nicer structure, move the "roles" directory out into the root
directory as well and add a symlink so everything still works.

Also see:
https://docs.ansible.com/ansible/latest/playbook_guide/playbook_pathing.html#resolving-local-relative-paths
https://docs.ansible.com/ansible/latest/playbook_guide/playbooks_reuse_roles.html#storing-and-finding-roles

roles/nginx/tasks/main.yaml

@@ -0,0 +1,19 @@
+- name: make sure nginx configuration names are valid
+  ansible.builtin.include_role:
+    name: nginx
+    tasks_from: make_sure_nginx_configuration_names_are_valid
+
+- name: make sure NGINX repos are setup
+  ansible.builtin.include_role:
+    name: nginx
+    tasks_from: main/repo_setup
+
+- name: make sure NGINX is installed
+  ansible.builtin.include_role:
+    name: nginx
+    tasks_from: main/nginx_install
+
+- name: make sure desirable NGINX configs are deployed
+  ansible.builtin.include_role:
+    name: nginx
+    tasks_from: main/config_deploy

roles/nginx/tasks/main/config_deploy.yaml

@@ -0,0 +1,132 @@
+- name: check, if a save of a previous `nginx.conf` is present
+  ansible.builtin.stat:
+    path: /etc/nginx/nginx.conf.ansiblesave
+  register: nginx__nginx_conf_ansiblesave_stat_result
+
+- name: handle the case, where a custom `nginx.conf` is to be used
+  when: nginx__use_custom_nginx_conf
+  block:
+    - name: when no `nginx.conf.ansiblesave` is present, save the current `nginx.conf`
+      when: not nginx__nginx_conf_ansiblesave_stat_result.stat.exists
+      ansible.builtin.copy:
+        force: true
+        dest: /etc/nginx/nginx.conf.ansiblesave
+        mode: "0644"
+        owner: root
+        group: root
+        remote_src: true
+        src: /etc/nginx/nginx.conf
+      become: true
+
+    - name: deploy the custom `nginx.conf`
+      ansible.builtin.copy:
+        content: "{{ nginx__custom_nginx_conf }}"
+        dest: "/etc/nginx/nginx.conf"
+        mode: "0644"
+        owner: root
+        group: root
+      become: true
+      notify: Restart `nginx.service`
+
+- name: handle the case, where no custom `nginx.conf` is to be used
+  when: not nginx__use_custom_nginx_conf
+  block:
+    - name: when a `nginx.conf.ansiblesave` is present, copy it to `nginx.conf`
+      when: nginx__nginx_conf_ansiblesave_stat_result.stat.exists
+      ansible.builtin.copy:
+        force: true
+        dest: /etc/nginx/nginx.conf
+        mode: "0644"
+        owner: root
+        group: root
+        remote_src: true
+        src: /etc/nginx/nginx.conf.ansiblesave
+      become: true
+      notify: Restart `nginx.service`
+
+    - name: delete the `nginx.conf.ansiblesave`, if it is present
+      when: nginx__nginx_conf_ansiblesave_stat_result.stat.exists
+      ansible.builtin.file:
+        path: /etc/nginx/nginx.conf.ansiblesave
+        state: absent
+      become: true
+
+- name: make sure mozilla dhparam is deployed
+  ansible.builtin.get_url:
+    force: true
+    dest: /etc/nginx-mozilla-dhparam
+    mode: "0644"
+    url: https://ssl-config.mozilla.org/ffdhe2048.txt
+  become: true
+  notify: Restart `nginx.service`
+
+- name: set `nginx__config_files_to_exist` fact initially to an empty list
+  ansible.builtin.set_fact:
+    nginx__config_files_to_exist: [ ]
+
+- name: handle the case, where tls.conf should be deployed
+  when: nginx__deploy_tls_conf
+  block:
+    - name: make sure tls.conf is deployed
+      ansible.builtin.copy:
+        force: true
+        dest: /etc/nginx/conf.d/tls.conf
+        mode: "0644"
+        owner: root
+        group: root
+        src: tls.conf
+      become: true
+      notify: Restart `nginx.service`
+
+    - name: add tls.conf to nginx__config_files_to_exist
+      ansible.builtin.set_fact:
+        nginx__config_files_to_exist: "{{ nginx__config_files_to_exist + [ 'tls.conf' ] }}"  # noqa: jinja[spacing]
+
+- name: handle the case, where redirect.conf should be deployed
+  when: nginx__deploy_redirect_conf
+  block:
+    - name: make sure redirect.conf is deployed
+      ansible.builtin.copy:
+        force: true
+        dest: /etc/nginx/conf.d/redirect.conf
+        mode: "0644"
+        owner: root
+        group: root
+        src: redirect.conf
+      become: true
+      notify: Restart `nginx.service`
+
+    - name: add redirect.conf to nginx__config_files_to_exist
+      ansible.builtin.set_fact:
+        nginx__config_files_to_exist: "{{ nginx__config_files_to_exist + [ 'redirect.conf' ] }}"  # noqa: jinja[spacing]
+
+- name: make sure all given configuration files are deployed
+  ansible.builtin.copy:
+    content: "{{ item.content }}"
+    dest: "/etc/nginx/conf.d/{{ item.name }}.conf"
+    mode: "0644"
+    owner: root
+    group: root
+  become: true
+  loop: "{{ nginx__configurations }}"
+  notify: Restart `nginx.service`
+
+- name: add names plus suffix from `nginx__configurations` to `nginx__config_files_to_exist` fact
+  ansible.builtin.set_fact:
+    nginx__config_files_to_exist: "{{ nginx__config_files_to_exist + [ item.name + '.conf' ] }}"  # noqa: jinja[spacing]
+  loop: "{{ nginx__configurations }}"
+
+- name: find configuration files to remove
+  ansible.builtin.find:
+    paths: /etc/nginx/conf.d/
+    recurse: false
+    excludes: "{{ nginx__config_files_to_exist }}"
+  register: nginx__config_files_to_remove
+
+- name: remove all configuration file, which should be removed
+  ansible.builtin.file:
+    path: "{{ item.path }}"
+    state: absent
+  become: true
+  loop: "{{ nginx__config_files_to_remove.files }}"
+  notify: Restart `nginx.service`

roles/nginx/tasks/main/nginx_install.yaml

@@ -0,0 +1,13 @@
+- name: make sure the `nginx` package is installed
+  ansible.builtin.apt:
+    name: nginx={{ nginx__version_spec }}*
+    state: present
+    allow_change_held_packages: true
+    update_cache: true
+  become: true
+
+- name: apt-mark hold `nginx`
+  ansible.builtin.dpkg_selections:
+    name: nginx
+    selection: hold
+  become: true

roles/nginx/tasks/main/repo_setup.yaml

@@ -0,0 +1,51 @@
+- name: gather package facts
+  ansible.builtin.package_facts:
+    manager: apt
+
+- name: make sure `gnupg` package is installed
+  ansible.builtin.apt:
+    name: gnupg
+    state: present
+    update_cache: true
+  become: true
+  when: "'gnupg' not in ansible_facts.packages"
+
+- name: make sure NGINX signing key is added
+  ansible.builtin.get_url:
+    url: https://nginx.org/keys/nginx_signing.key
+    dest: /etc/apt/trusted.gpg.d/nginx.asc
+    mode: "0644"
+    owner: root
+    group: root
+  become: true
+  notify: apt-get update
+
+- name: make sure NGINX APT repository is added
+  ansible.builtin.apt_repository:
+    repo: "deb [arch=amd64 signed-by=/etc/apt/trusted.gpg.d/nginx.asc] https://nginx.org/packages/debian/ {{ ansible_distribution_release }} nginx"
+    state: present
+  become: true
+  notify: apt-get update
+
+- name: make sure NGINX APT source repository is added
+  ansible.builtin.apt_repository:
+    repo: "deb-src [arch=amd64 signed-by=/etc/apt/trusted.gpg.d/nginx.asc] https://nginx.org/packages/debian/ {{ ansible_distribution_release }} nginx"
+    state: present
+  become: true
+  notify: apt-get update
+
+- name: set up repository pinning to make sure nginx package gets installed from NGINX repositories
+  ansible.builtin.copy:
+    content: |
+      Package: *
+      Pin: origin nginx.org
+      Pin: release o=nginx
+      Pin-Priority: 900
+    dest: /etc/apt/preferences.d/99nginx
+    owner: root
+    group: root
+    mode: "0644"
+  become: true
+
+- name: Flush handlers to make sure "apt-get update" handler runs, if needed
+  ansible.builtin.meta: flush_handlers

roles/nginx/tasks/make_sure_nginx_configuration_names_are_valid.yaml

@@ -0,0 +1,6 @@
+- name: make sure nginx configuration names are valid
+  ansible.builtin.fail:
+    msg: "You used the following name: `{{ item.name }}`. Please make sure to not use the following names: `tls`, `redirect`."
+  when: item.name == "tls"
+        or item.name == "redirect"
+  loop: "{{ nginx__configurations }}"