Swap out email/pass auth (read as devise) for chef_oauth2 with developer as the provider

:construction_worker: 

this is still a work in progress, but it is moving along. devise has been removed and omniauth for auth has been added back in. it is just using the developer strategy, which should be switched out for a chef strategy that uses oc-id.

todo:

- [x] write chef omniauth strategy - [yey I think this was already done](https://github.com/opscode/omniauth-chef-oauth2)
- [x] refactor omniauth mock_auth stufffff
- [x] replace developer strat with chef strat
- [x] refactor/replace the lib methods that I copypastaed from devise - `lib/supermarket/location_storage`
- [x] write specs and document all the changes
- [x] test against oc-id in production
- [x] write migration to remove unneeded devise attrs on user
- [x] make sure all of the devise files are gone
- [x] get da specs passing

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This pull request closes #182.