Refactor: migrate cmp/* and srv/* roles into sys-stk/* and sys-svc/* namespaces

- Removed obsolete 'cmp' category, introduced 'stk' category (fa-bars-staggered icon).
- Renamed roles:
  * cmp-db-docker → sys-stk-back-stateful
  * cmp-docker-oauth2 → sys-stk-back-stateless
  * srv-domain-provision → sys-stk-front
  * cmp-db-docker-proxy → sys-stk-full-stateful
  * cmp-docker-proxy → sys-stk-full-stateless
  * cmp-rdbms → sys-svc-rdbms
- Updated all include_role references, vars, templates and README.md files.
- Adjusted run_once comments and variable paths accordingly.
- Updated all web-app roles to use new sys-stk/* and sys-svc/* roles.

Conversation: https://chatgpt.com/share/68b0ba66-09f8-800f-86fc-76c47009d431

roles/sys-stk-back-stateful/meta/main.yml

@@ -0,0 +1,17 @@
+galaxy_info:
+  author: "Kevin Veen-Birkenbach"
+  description: >
+    Combines Docker Compose with a central RDBMS role to automatically
+    provision database containers with backup, user, and permission management.
+  company: |
+    Kevin Veen-Birkenbach
+    Consulting & Coaching Solutions
+    https://www.veen.world
+  license: "Infinito.Nexus NonCommercial License"
+  license_url: "https://s.infinito.nexus/license"
+  galaxy_tags:
+    - docker
+    - database
+    - rdbms
+    - backup
+    - compose