General optimations and refactorings in preparation for simpleicon role implementation

roles/docker-wordpress/tasks/install.yml

@@ -2,7 +2,7 @@
   command: >
     docker-compose exec -T -u www-data application
     wp core install
-      --url="{{ web_protocol }}://{{ domains | get_domain(application_id) }}"
+      --url="{{ domains | get_url(application_id, web_protocol) }}"
       --title="{{ applications[application_id].title }}"
       --admin_user="{{ applications[application_id].users.administrator.username }}"
       --admin_password="{{ applications[application_id].credentials.administrator_password }}"

roles/docker-wordpress/vars/discourse.yml

@@ -11,7 +11,7 @@ discourse_settings:
 
   - name: discourse_connect
     key: url
-    value: "{{ web_protocol }}://{{ domains | get_domain('discourse') }}"
+    value: "{{ domains | get_url('discourse', web_protocol) }}"
   - name: discourse_connect
     key: api-key
     value: "{{ vault_discourse_api_key }}"