[Meta] Extractor issues in extractor

[kubo6472]

Checklist

• I checked, but didn't find any duplicates (open OR closed) of this issue in the repo. Technically Better triaging and faster releases #3940
• I have read the contribution guidelines given at https://github.com/TeamNewPipe/NewPipe/blob/HEAD/.github/CONTRIBUTING.md.
• This issue contains only one feature request. I will open one issue for every feature I want to request.

Describe the feature you want

Adding some clear instructions, that extractor issues should go exclusively to extractor repo and who should be responsible moving them there, etc.

Is your feature request related to a problem? Please describe it

I made possibly the greatest "gray-area" example issue for this, as I thought it's an extractor thing, to get newpipe to support "local youtube-dl" like FreeTube, but I formulated the issue like: "switch away from using the extractor" so it was technically a newpipe issue. (Just read it for the context TeamNewPipe/NewPipeExtractor#466)

[opusforlife2]

New issue forms solved this.