Allow users to add projects in teams from self hosted GitLab providers

[gtsiolis]

Problem to solve

The upcoming Teams & Projects feature supports adding repositories from GL (gitlab.com) and GH (github.com) but does not support projects from self hosted GitLab instances.

See also relevant discussion in #5113 (comment). Cc @AlexTugarev

Risks

This would require first to introduce any safety mechanisms that make the dashboard usable even if the self hosted instances go offline. Such mechanisms could include caching information (see #5038) or using skeleton loaders to handle any slow connection issues (see #5075).

[AlexTugarev]

@gtsiolis, I suggest to limit the scope of this issue to self-managed GitLabs. We assume that it will work with little changes, just by relaxing the blocker.

With GHE things look much different. The configuration part of GItHub Prebuilds requires to generate a key and import it into Gitpod, which is currently supported at deploy-time only.

[gtsiolis]

Sounds absolutely reasonable, @AlexTugarev! I've only added this to avoid missing both points. Renamed this issue for GitLab self hosted and opened #5297 for supporting GitHub self hosted which I'd think also has a lower priority than this one. 🔅

[gtsiolis]

This was recently brought up in our discord server, see relevant discussion. Cc @jldec

[jldec]

#5095 (comment)

[JanKoehnlein]

/schedule

[roboquat]

@JanKoehnlein: Issue scheduled in the meta team (WIP: 0)

In response to this:

/schedule

Instructions for interacting with me using PR comments are available here. If you have questions or suggestions related to my behavior, please file an issue against the kubernetes/test-infra repository.

[AlexTugarev]

/assign

[AlexTugarev]

This would require first to introduce any safety mechanisms that make the dashboard usable even if the self hosted instances go offline.

@gtsiolis, just from re-reading the issue, I don't think tackling these risks is in scope of the PR to initially support self-managed GitLab instances. preserving details from remote services is a general improvement not directly depending on the provider.