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/ola/meta/argument_specs.yaml

@@ -0,0 +1,22 @@
+---
+argument_specs:
+  main:
+    options:
+      ola__configs:
+        description: A list of ola configurations.
+        type: list
+        elements: dict
+        required: true
+        options:
+          name:
+            description: >-
+              The name of the configuration file, where the configuration should
+              be deployed to. The file will be placed under `/etc/ola/` and
+              `.conf` will be appended to the given name. So in the end the path
+              will be like this: `/etc/ola/\{\ name \}\}.conf`.
+            type: str
+            required: true
+          content:
+            description: The content of the configuration.
+            type: str
+            required: true

roles/ola/meta/main.yaml

@@ -0,0 +1,8 @@
+---
+dependencies:
+  - role: distribution_check
+    vars:
+      distribution_check__distribution_support_spec:
+        - name: Debian
+          major_versions:
+            - "11"