add aws s3 placeholder variables

docker/plays/credentials.yml

@@ -9,4 +9,4 @@
     - nginx
     - role: credentials
       nginx_default_sites:
-        - credentials
\ No newline at end of file
+        - credentials

playbooks/roles/credentials/defaults/main.yml

@@ -84,6 +84,10 @@ CREDENTIALS_SERVICE_CONFIG:
 
   PLATFORM_NAME: '{{ CREDENTIALS_PLATFORM_NAME }}'
 
+  AWS_STORAGE_BUCKET_NAME: ''
+  AWS_ACCESS_KEY_ID: ''
+  AWS_SECRET_ACCESS_KEY: ''
+
 
 CREDENTIALS_REPOS:
   - PROTOCOL: "{{ COMMON_GIT_PROTOCOL }}"