SCM Inventory model, view, and task system changes

Inventory source file-type combined with a linked project
will allow the inventory source to be updated when the
project is updated. The inventory update runs in the
post-run hook of the project update.

awx/main/access.py

@@ -765,9 +765,12 @@ class InventorySourceAccess(BaseAccess):
         else:
             return False
 
+    @check_superuser
     def can_add(self, data):
         if not data or 'inventory' not in data:
             return False
+        if not self.check_related('scm_project', Project, data, role_field='admin_role'):
+            return False
         # Checks for admin or change permission on inventory.
         return self.check_related('inventory', Inventory, data)