feat: show status when running gimmegit in a clone

[dwilding]

This PR adds a status output when gimmegit is run in a clone. For example:

~/work$ cd jubilant/dwilding-my-feature
~/work/jubilant/dwilding-my-feature$ gimmegit
Project    Base branch      Review branch (not created)
jubilant   canonical:main   dwilding:my-feature

If color is supported, the base branch and review branch link to GitHub.