This will prevent us from running out of auto-incrementing ID values until such time as we can upgrade to peewee 3 and change the field type to a BigInt
Fixes https://jira.coreos.com/browse/QUAY-943
Instead of disabling repo names with periods in them, we simply disallow calls to the API when they are GET requests, whose path ends in a dot, and that do not have a referrer from the frontend.
We move all the auth handling, serialization and deserialization into a new AuthContext interface, and then standardize a registration model for handling of specific auth context types (user, robot, token, etc).
