Move the auth context methods into their own file so that we don't have auth trying to import itself

auth/auth_context.py

@@ -0,0 +1,7 @@
+from flask import _request_ctx_stack
+
+def get_authenticated_user():
+  return getattr(_request_ctx_stack.top, 'authenticated_user', None)
+
+def get_validated_token():
+  return getattr(_request_ctx_stack.top, 'validated_token', None)