squash! virt: Rewrite github_issues tool

* Renamed github_issues -> libpygh since it sits ontop of pygithub
  and now handles much more than just issues.

Signed-off-by: Chris Evich <cevich@redhat.com>
fixup: virt: Rewrite github_issues tool

Signed-off-by: Chris Evich <cevich@redhat.com>