Bug/oauth login - Githubissues

Fixes #651

Changes proposed in this PR:

Fix CSS issues with Doorkeeper Oauth2 sign in and authorization pages
Doorkeeper and Devise gems had been updated I guess since this was last tests and verified to be working a couple of years ago. They are now using Rails strict params. Spent around 16 hours digging through Devise and Doorkeeper documentation and code 🤯 to figure out how and where to adjust our customizations to the vanilla Doorkeeper pages, controllers, helpers and model hooks working together again
Adjusted sessions and omniauth controllers to work with the auth-referer info
Adjusted doorkeeper views

No really a good way to test this.

You need to install the code from the api_tester repo.
Run the api_test app in one tab.
Enter in the url for the stage site and select api v2
Log into the stage site as a super admin in a different browser
Go to the ApiClients page and select a client
Copy their client id and secret
Paste the client id and secret into the api_test app page and click the 'Fetch Single DMP' button under the 'For an ApiClient (On a User's behalf)' section.
Sign in using SSO and then authorize it

Then repeat the above for a non SSO login and also with (SSO and non-SSO again and 'deny' the authorization.

CDLUC3 / dmptool