External User Creation Without Whitelisted Domain

Description

When a company has a hosted GitLab, it makes sense to Whitelist the company domain to ensure that only users (in this case coming through google oauth) from the company are able to gain access. However, this also blocks an admin when creating a new external user.

Proposal

Allow external users to be created by an admin with a non-whitelisted domain, and for those users to login.

Links / references

added ~17488 oauth labels

added ~12980 ~131895 labels

I've added labels to this issue to identify it as a bug.

mentioned in merge request gitlab-com/www-gitlab-com!4080 (merged)

added ~123454 label

mentioned in merge request !8575 (merged)

added ~164274 label

assigned to @godfat

mentioned in issue #27028 (moved)

removed ~123454 ~131895 labels

closed via merge request !8575 (merged)

mentioned in issue #3202 (closed)

mentioned in issue gitlab#7899