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-svc-rdbms/templates/services/postgres.yml.j2

@@ -0,0 +1,22 @@
+{# This template needs to be included in docker-compose.yml, which depend on a postgres database #}
+
+{% if not applications | get_app_conf(application_id, 'features.central_database', False) %}  
+  {{ database_host }}:
+    image: postgres:{{applications['svc-db-postgres'].version}}-alpine
+    container_name: {{ application_id | get_entity_name }}-database
+    env_file:
+      - {{database_env}}
+    restart: {{ DOCKER_RESTART_POLICY }}
+    healthcheck:
+      test: ["CMD-SHELL", "pg_isready -U {{ database_name }}"]
+      interval: 10s
+      timeout: 5s
+      retries: 6
+    volumes:
+      - type:   volume
+        source: database
+        target: /var/lib/postgresql/data
+    networks:
+      - default
+{% endif %}
+{{ "\n" }}