Refactor role naming for TLS and proxy stack

- Renamed role `srv-tls-core` → `sys-svc-certs`
- Renamed role `srv-https-stack` → `sys-stk-front-pure`
- Renamed role `sys-stk-front` → `sys-stk-front-proxy`
- Updated all includes, READMEs, meta, and dependent roles accordingly

This improves clarity and consistency of naming conventions for certificate management and proxy orchestration.

See: https://chatgpt.com/share/68b19f2c-22b0-800f-ba9b-3f2c8fd427b0

roles/web-app-matrix/tasks/03_webserver.yml

@@ -9,9 +9,9 @@
     src:  "well-known.j2" 
     dest: "{{ MATRIX_WELL_KNOWN_FILE }}"
         
-- name: "include role sys-stk-front for {{ MATRIX_ELEMENT_DOMAIN }}"
+- name: "include role sys-stk-front-proxy for {{ MATRIX_ELEMENT_DOMAIN }}"
   include_role: 
-    name: sys-stk-front
+    name: sys-stk-front-proxy
   vars:        
     domain:     "{{ MATRIX_ELEMENT_DOMAIN }}"
     http_port:  "{{ MATRIX_ELEMENT_PORT }}"