[Spike] Investigate which special-cased authentication configuration we can remove/update now that some of it has been upstreamed

[GeorgianaElena]

After we've migrated the hubs to use z2jh4, we will be using a more recent oauthenticator version, 17.1.0 that comes with some changes

We should investigate removing/updating the hubs that still use special-cased configuration that has now been upstreamed in this version of oauthenticator (earthscope, hubs using managed_groups and GitHubOauthenticator)

Definition of Done

• the config that needs to be updated or removed has been identified (if any)