Dynamically collect secrets for backup & restore roles

- This prevents us from overwriting vars unintentionally at restore time
  - This will make it easier to add secrets to be backed up in the future
  - Add generated secret names to awx spec backup
  - Fail early if secret status doesn't exist
  - Skip if secret is not in spec for non-generated secrets
  - Secret values must be b64 decoded before secret is created
  - Cleanup temp files

roles/backup/tasks/main.yml

@@ -30,10 +30,10 @@
 
     - include_tasks: postgres.yml
 
-    - include_tasks: secrets.yml
-
     - include_tasks: awx-cro.yml
 
+    - include_tasks: secrets.yml
+
     - name: Set flag signifying this backup was successful
       set_fact:
         backup_complete: true
@@ -45,5 +45,3 @@
 
 - name: Update status variables
   include_tasks: update_status.yml
-
-# TODO: backup tower settings or make sure that users only specify settings/config changes via AWX object.  See ticket