chore: standardize YAML file extensions

Use .yml consistently across role metadata and tooling configuration.

Co-authored-by: Copilot <copilot@github.com>

meta/main.yml

@@ -0,0 +1,24 @@
+dependencies: []
+galaxy_info:
+  author: "Markus Pesch"
+  company: Cryptic Systems
+  description: Role to configure root
+  galaxy_tags:
+  - root
+  license: MIT
+  min_ansible_version: "2.9"
+  namespace: volker-raschek
+  platforms:
+  - name: ArchLinux
+    versions:
+    - all
+  - name: EL
+    versions:
+    - all
+  - name: Fedora
+    versions:
+    - all
+  - name: Ubuntu
+    versions:
+    - all
+  role_name: "root"