implement custom user types via POST

[mpdehaan]

see https://docs.google.com/document/d/14yZo34KXeDGtHMKVuL7CrbEwxEwaN7jK1IkP9Oe-81k/edit

User Configurable Columns and Data

New tables UserType and UserData Stores in UserData a repo and a type and value1, value2, … Stores in UserType the types of value1 and value2 and some display header info Be able to post user Data over REST with an API key JSON endpoints for repo detail and repo both include configured user data What user data gets sent in the JSON is configured by attaching UserTypes to two fields in the Organization config, ListUserTypes and DetailUserTypes (?) - or similar - not configured in settings.py Columns show up in Repo List Shows tabularly in Repo Detail