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/README.md

@@ -0,0 +1,30 @@
+# Central Database
+
+## Description
+
+This Ansible role provisions a centralized database system in your Docker Compose environment. It supports both MariaDB and PostgreSQL, providing a robust, scalable, and low-maintenance database solution. Whether you're consolidating your application's data or creating a dedicated central storage, this role simplifies setup and integration.
+
+## Overview
+
+Tailored for environments that require a central data repository, this role:
+- Loads necessary database variables defined in [vars/database.yml](./vars/database.yml).
+- Generates an environment file based on the chosen database engine.
+- Integrates seamlessly with Docker Compose to deploy a centralized database container (if enabled).
+
+## Purpose
+
+The role's purpose is to automate the provisioning and configuration of a centralized database service. This not only reduces manual setup but also ensures consistent, reliable deployment across production and homelab environments.
+
+## Features
+
+- **Supports Multiple Engines:** Easily switch between MariaDB and PostgreSQL.
+- **Centralized Data Management:** Improves data consistency and security.
+- **Docker Compose Integration:** Automates container setup and configuration.
+- **Simplified Variable Management:** Preconfigured templates minimize manual intervention.
+
+## Credits 📝
+
+Developed and maintained by **Kevin Veen-Birkenbach**.  
+Learn more at [www.veen.world](https://www.veen.world)  
+Part of the [Infinito.Nexus Project](https://s.infinito.nexus/code)  
+License: [Infinito.Nexus NonCommercial License](https://s.infinito.nexus/license)