FR: `lab project create` for a different namespace

[krlmlr]

lab project create --namespace 7

# Even better:
lab project create group/repo

The GitLab API seems to require a numeric namespace identifier, which needs to be looked up. We might want to implement a groups command too.

[zaquestion]

Agree you should be able to just type the namespace along with the project. It's what feels natural

[abeluck]

This would be really great!

[bmeneg]

Feature added with MR #450