Move GitLab repositories to AngusGit: import public projects, push private and internal ones

A public project on an intranet GitLab can be moved into AngusGit with Import repository, which brings only the files that were on the default branch. The imported xlliu/hello-world-import is that result: main only. Internal and private projects are cloned with --bare and pushed into an empty repository whose path follows the subgroup rule.