Gitlab: Auto-discover and adopt MRs created on Gitlab

[prclm]

I tested the integration with Gitlab and want to request a feature regarding MergeRequests.

GitButler by now does not detect MRs that already exist in Gitlab.
We use Templates and Labels in Gitlab which are added when creating a MR from Gitlab Dashboard.

On the other hand, when creating a MR from Gitbutler, there are no Template and Labels assinged.

It would be awesome if Gitbutler would detected the MRs and give an option to "adopt" these.

[prclm]

A workaround for now is adding the "pr_number" inside the virtual_branches.toml by hand.

[Byron]

Thanks a lot for reporting, and for sharing the workaround!

If I ever get to #12263, that will be a bit harder though.

However, it's certainly functionality that will move more and more to the backend, and maybe that's the time when it will be generalised.