setup-pureos-pkg-repo: allow to mirror from salsa

Currently there's three steps:

• mirror from salsa via web-ui
• create a pureos/latest branch (via web-ui or clone)
• run setup-pureos-pkg-repo on it

This should be a single step.

what is setup-pureos-pkg-repo - is that in some PureOS-specific package or in Gitlab or...?

It's even part of the repo the bug was filed against: https://source.puri.sm/Librem5/librem5-dev-tools/-/blob/master/setup-pureos-pkg-repo

@jonas.smedegaard since the whole thing doesn't have a manpage (patches welcome): it basically sets up the repo in gitlab (branch protection, ci file name, ...). Mostly a band aid to safe me repetitive work.

mentioned in issue #3 (closed)

Thanks for clarifying - makes sense now.

I stupidly forgot to reflect on the context of the bug - treated it similar to those free-floating notes, and was lead here from a conversation in the PureOS room where you referenced this as seemingly part of a here's-how-to-get-started-with-PureOS-hacking guidance. I was concerned if you were making assumptions about unusual tools being generally available to PureOS developers.

I realize now that this is a Librem5-specific developer's tool, and my concerns are moot (I am just still puzzled as to the relevancy of referencing it in a beginner-to-PureOS-developemnt context - but that's independent of this issue tracking!) - sorry for the noise.

It seems that python3-gitlab (currently) does not provide API to import from an arbitrary URL (only from bitbucket, github or an archive file) https://python-gitlab.readthedocs.io/en/stable/api/gitlab.v4.html#gitlab.v4.objects.ProjectManager.gitlab

Docs on the REST API for the curious: https://docs.gitlab.com/ee/api/project_import_export.html#import-a-file-from-a-remote-object-storage