Fixes to make learn work with scim-for-keycloak

[rhysyngsun]

What are the relevant tickets?

Closes https://github.com/mitodl/hq/issues/5562

Description (What does it do?)

This adds changes to make the SCIM integration work with the scim-for-keycloak plugin.

This includes changes from #1682 that were reverted in #1723, but since we need something slightly different for scim-for-keycloak I just combined them here with the additional adjustments.

How can this be tested?

• Sign up for a free account on https://scim-for-keycloak.de/ and download the JAR file.
• Put that JAR file in your providers/ directory in your keycloak install.
• Follow the installation steps: https://scim-for-keycloak.de/documentation/installation/install
• You probably want to run keycloak with - --spi-realm-restapi-extension-scim-repair-database=true once so it migrates existing realms
• Go to your Learn API django-admin and create an Application and Access Token and save the token value for later.
• Go to http://keycloak.odl.local:8080/ and click on the link to the SCIM admin console. Login to the master realm.
• Go the the realm management page and edit your realm for Learn. Toggle "SCIM Enabled" and save.
• Go to the Remote SCIM Provider page and click the "+" button to create a new provider.
  • Use any name.
  • Enter the base url for Learn that is reachable from your keycloak instance. If you're running keycloak on your host system this is probably http://open.odl.local:8063/scim/v2/ or similar.
  • In the Authorization section, switch to Long Life Bearer Token Authentication. Enter the Access Token value from the Learn django-admin.
  • Click "Save Configuration"
• Click "Use Default Configuration" at the bottom of the page. You should see new tabs appear. Navigate to the "Realm Assignments" tab.
• Assign this provider to your Learn realm.
• Switch to the "Schemas" tab and edit the User schema:
  • Update the displayName attribute to use the custom attribute "fullName".
  • Add a new attribute:
    • Name: emailOptIn
    • Type: integer
    • Custom Attribute Name: emailOptIn
    • Everything else leave the defaults.
• At this point you should be able to switch to the "Synchronization" tab and walk through a full synchronization of users.
• You should also be able to create/update users without hitting Learn (the keycloak admin is an easy way to do this).