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-elk/tasks/main.yml

@@ -1,8 +1,8 @@
 ---
 
-- name: "include role sys-stk-front for {{ application_id }}"
+- name: "include role sys-stk-front-proxy for {{ application_id }}"
   include_role:
-    name: sys-stk-front
+    name: sys-stk-front-proxy
   vars:
     domain:   "{{ domains | get_domain(application_id) }}"
     http_port:   "{{ ports.localhost.http[application_id] }}"