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/distribution_check/README.md

@@ -0,0 +1,13 @@
+# Role `distribution_check`
+
+This role checks if the distribution of the hosts is supported (part of the provided distribution support spec.) and fails if it's not.
+
+If a hosts distribution and either an accompanying distribution version, major version or release is supported, the role doesn't fail for the host in question.
+
+## Required Arguments
+
+For the required arguments look at the [`argument_specs.yaml`](./meta/argument_specs.yaml).
+
+## `hosts`
+
+The `hosts` for this role need to be the machines for which you want to make sure their distribution is supported.

roles/distribution_check/meta/argument_specs.yaml

@@ -0,0 +1,28 @@
+argument_specs:
+  main:
+    options:
+      distribution_check__distribution_support_spec:
+        description: A spec specifying the supported distribution.
+        type: list
+        elements: dict
+        required: true
+        options:
+          name:
+            description: The name of the supported distribution.
+            type: str
+            required: true
+          versions:
+            description: The supported versions of the supported distribution.
+            type: list
+            elements: str
+            required: false
+          major_versions:
+            description: The supported major versions of the supported distribution.
+            type: list
+            elements: str
+            required: false
+          releases:
+            description: The supported releases of the supported distribution.
+            type: list
+            elements: str
+            required: false

roles/distribution_check/tasks/main.yaml

@@ -0,0 +1,53 @@
+- name: set fact holding list of supported distribution names
+  ansible.builtin.set_fact:
+    distribution_check__supported_distribution_names: "{{ distribution_check__distribution_support_spec
+      | community.general.json_query('[].name') }}"
+
+- name: fail on unsupported distribution (name)
+  ansible.builtin.fail:
+    msg: The hosts distribution (name) isn't supported.
+  when: ansible_facts['distribution'] not in distribution_check__supported_distribution_names
+
+- name: set facts for holding lists of supported distribution versions, major versions and releases
+  block:
+    - name: set fact holding list of supported distribution versions
+      ansible.builtin.set_fact:
+        distribution_check__supported_distribution_versions: "{{ distribution_check__distribution_support_spec
+          | community.general.json_query(distribution_check__supported_distribution_versions_query) }}"
+      vars:
+        distribution_check__supported_distribution_versions_query: "[?name=='{{ ansible_facts['distribution'] }}'].versions | [].to_string(@)"
+
+    - name: set fact holding list of supported distribution major versions
+      ansible.builtin.set_fact:
+        distribution_check__supported_distribution_major_versions: "{{ distribution_check__distribution_support_spec
+          | community.general.json_query(distribution_check__supported_distribution_major_versions_query) }}"
+      vars:
+        distribution_check__supported_distribution_major_versions_query: "[?name=='{{ ansible_facts['distribution'] }}'].major_versions | [].to_string(@)"
+
+    - name: set fact holding list of supported distribution releases
+      ansible.builtin.set_fact:
+        distribution_check__supported_distribution_releases: "{{ distribution_check__distribution_support_spec
+          | community.general.json_query(distribution_check__supported_distribution_releases_query) }}"
+      vars:
+        distribution_check__supported_distribution_releases_query: "[?name=='{{ ansible_facts['distribution'] }}'].releases | [].to_string(@)"
+
+- name: check for distribution version, major version and release support
+  block:
+    - name: set fact on whether the distribution version is supported
+      ansible.builtin.set_fact:
+        distribution_check__distribution_version_supported: "{{ ansible_facts['distribution_version'] in distribution_check__supported_distribution_versions }}"
+
+    - name: set fact on whether the distribution major version is supported
+      ansible.builtin.set_fact:
+        distribution_check__distribution_major_version_supported: "{{ ansible_facts['distribution_major_version'] in distribution_check__supported_distribution_major_versions }}"  # noqa: yaml[line-length]
+
+    - name: set fact on whether the distribution release is supported
+      ansible.builtin.set_fact:
+        distribution_check__distribution_release_supported: "{{ ansible_facts['distribution_release'] in distribution_check__supported_distribution_releases }}"
+
+- name: fail, if neither the distributions version, major version or release is supported
+  ansible.builtin.fail:
+    msg: Neither the hosts distribution version, major version or release is supported.
+  when: not (distribution_check__distribution_version_supported
+             or distribution_check__distribution_major_version_supported
+             or distribution_check__distribution_release_supported)