Add centralized include for Access-Control-Allow headers across proxy/service Nginx templates and align ACA vars for simpleicons task.

Ref: https://chatgpt.com/share/68dbf59c-f424-800f-aa27-787db52e260f

roles/web-svc-simpleicons/tasks/main.yml

@@ -4,10 +4,9 @@
     include_role:
       name: sys-stk-full-stateless
     vars:
-      aca_origin:   "* always"
-      aca_methods:  "'GET, OPTIONS' always"
-      aca_headers:  "'Accept, Authorization, Content-Type' always"
-
+      aca_origin:  "* always"
+      aca_methods: "'GET, OPTIONS' always"
+      aca_headers: '"Origin, X-Requested-With, Content-Type, Accept, Authorization" always'
   - name: "Copy '{{ application_id }}' files"
     template:
       src: "{{ item.source }}"