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-full-stateful/README.md

@@ -0,0 +1,11 @@
+# Database Docker with Web Proxy
+
+This role builds on `sys-stk-back-stateful` by adding a reverse-proxy frontend for HTTP access to your database service.
+
+## Features
+
+- **Database Composition**  
+  Leverages the `sys-stk-back-stateful` role to stand up your containerized database (PostgreSQL, MariaDB, etc.) with backups and user management.
+
+- **Reverse Proxy**  
+  Includes the `sys-stk-front` role to configure a proxy (e.g. nginx) for routing HTTP(S) traffic to your database UI or management endpoint.