Add `gh search repo` picker

[Tarso Boudet Caldas]

GitHub CLI has, for sometime, the search argument, in which you can search repositories. This would be a great addition to this extension.

[Kyoichiro Yamada]

It would be nice to be able to open the issues, pull_request, and run selectors directly after selecting a repository.

e.g.

• <C-i>: open issues selector for the repository
• <C-p>: open pull_request
• <C-r>: open run