flatten the "playbooks" directory for better structure

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 flatten the playbooks directory to get rid of this confusing
structure.

Also see:
https://docs.ansible.com/ansible/latest/playbook_guide/playbook_pathing.html#resolving-local-relative-paths

roles/nextcloud/tasks/main.yaml

@@ -0,0 +1,58 @@
+---
+- name: wait for existence of config directory
+  ansible.builtin.wait_for:
+    path: /ansible_docker_compose/nextcloud_var_www_html/config
+    state: present
+  become: true
+
+- name: extra Nextcloud configuration
+  ansible.builtin.copy:
+    content: "{{ nextcloud__extra_configuration }}"
+    dest: /ansible_docker_compose/nextcloud_var_www_html/config/ansible_nextcloud_extra_config.config.php
+    mode: "0644"
+    owner: www-data
+    group: www-data
+  become: true
+
+- name: fail, if nextcloud__use_custom_new_user_skeleton is set, but nextcloud__custom_new_user_skeleton_directory isn't
+  ansible.builtin.fail:
+    msg: If you set nextcloud__use_custom_new_user_skeleton, you also need to set nextcloud__custom_new_user_skeleton_directory.
+  when: nextcloud__use_custom_new_user_skeleton and nextcloud__custom_new_user_skeleton_directory == ""
+
+- name: ensure custom new user skeleton
+  when: nextcloud__use_custom_new_user_skeleton
+  block:
+    - name: ensure `rsync` package is installed
+      ansible.builtin.apt:
+        name: rsync
+        state: present
+      become: true
+
+    - name: ensure custom new user skeleton directory
+      ansible.posix.synchronize:
+        src: "{{ nextcloud__custom_new_user_skeleton_directory }}"
+        dest: /ansible_docker_compose/custom_new_user_skeleton
+        delete: true
+        recursive: true
+        use_ssh_args: true
+      become: true
+
+    - name: ensure custom new user skeleton config
+      ansible.builtin.copy:
+        content: |
+          <?php
+          $CONFIG = array (
+              'skeletondirectory' => '/custom_new_user_skeleton'
+          );
+        dest: /ansible_docker_compose/nextcloud_var_www_html/config/ansible_nextcloud_custom_new_user_skeleton.config.php
+        mode: "0644"
+        owner: www-data
+        group: www-data
+      become: true
+
+- name: ensure absence of custom new user skeleton config
+  ansible.builtin.file:
+    path: /ansible_docker_compose/nextcloud_var_www_html/config/ansible_nextcloud_custom_new_user_skeleton.config.php
+    state: absent
+  become: true
+  when: not nextcloud__use_custom_new_user_skeleton