Renamed general and mode constants and implemented a check to verify that constants are just defined ones over the whole repository

roles/web-app-discourse/config/main.yml

@@ -16,10 +16,10 @@ server:
         unsafe-inline: true
     whitelist:
       font-src:
-        - "http://*.{{primary_domain}}"
+        - "http://*.{{PRIMARY_DOMAIN}}"
   domains:
     canonical:
-      - "forum.{{ primary_domain }}"
+      - "forum.{{ PRIMARY_DOMAIN }}"
 docker:
   services:
     database:

roles/web-app-discourse/tasks/01_core.yml

@@ -1,6 +1,6 @@
 - name: "reset (if enabled)"
   include_tasks: 02_reset.yml
-  when: mode_reset | bool
+  when: MODE_RESET | bool
 
 # Necessary for building: https://chat.openai.com/share/99d258cc-294b-4924-8eef-02fe419bb838
 - name: install which