- Add code for placing the features information on the frontend

- Add a Features service for examining feature flags on the frontend
- Add a directive (quay-requires) that matches feature flags and, if any one does not match, removes the element from the DOM
- Add a directive (quay-show) that injects the features into the scope so that expressions of the form "Features.BILLING || something" work out of the box to show/hide the element
- Add a directive (quay-classes) that allows for setting of CSS classes on an element based on feature expression(s) such as {"!BILLING": "active"} (e.g. the BILLING flag is set to false, add the class "active".

config.py

@@ -109,8 +109,15 @@ class DefaultConfig(object):
       STATUS_TAGS[tag_name] = tag_svg.read()
 
 
+  # Feature Flag: Whether billing is required.
   FEATURE_BILLING = False
 
+  # Feature Flag: Whether user accounts automatically have usage log access.
+  FEATURE_USER_LOG_ACCESS = True
+
+  # Feature Flag: Whether GitHub login is supported.
+  FEATURE_GITHUB_LOGIN = False
+
 
 class FakeTransaction(object):
   def __enter__(self):