[Enhancement] Expand Pull Request labels for code review

[syeopite]

Invidious currently has a lot of PRs and sorting through them to find which ones needs a review is a bit annoying.

I think it might be useful to add a couple more pull-request labels for pull-requests in the code review phase, to allow finding ones that needs to be reviewed easier, and ones that don't.

There's currently only a single one and that's need-code-review which is only used to mark PRs that haven't been reviewed yet.

So here's some new ones that I think we can add:

• stage: code-review marks a PR as being in the code-review stage and helps signify to contributors that their pull request hasn't been ignored.

• awaiting review (or simply tacked onto need-code-review) to mark PRs that needs to be reviewed after some changes were made

• awaiting author A review has been made and changes has been requested

• ongoing discussion An on-going discussion on some implementation detail that needs to be resolved before the PR can progress further

[unixfox]

Good for me!

[Fijxu]

Good for me too.