Convert to OAuth2 login provider instead of OIDC

Description

This changes our use of `auth-backends` from the deprecated OIDC provider to the OAuth2 provider, because I rebuilt my devstack and the OIDC one wasn't working.

This is working, however there are a couple issues:

Test instructions: See the instructions added to the README.

Done

Assignee

Unassigned

Reporter

Open Source Pull Request Bot

Labels

None

Contributor Name

Braden MacDonald

Repo

edx/blockstore

Customer

Epic Link

None

OSCM Assignee

None

Platform Map Area (Levels 1 & 2)

None

Platform Map Area (Levels 3 & 4)

None

Blended Hour Utilization Percentage

None

edX Theme

None

edX Squad

None

Github Lines Added

29

Github Lines Deleted

118

Priority

Unset