Allow local comments pinning in comments section

[tiwarys]

Checklist

• I checked, but didn't find any duplicates (open OR closed) of this issue in the repo.
• 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

I think it would be nice if you allow local comments pinning in comments section like local subscribe.

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

Sometimes we might see some useful comments in the comments section. If a video has many comments then it is difficult to scroll down and find our required comment.

Additional context

Screenshot from YouTube website

There is Pinned by The Hated One in the screenshot. In that place we can add something like Pinned by yourself or just Pinned Comments.

How will you/everyone benefit from this feature?

It would be very easy to track useful comments in comments section of a video.

[Orion983]

I'd find this very useful. Great idea!

[Stypox]

This would be problematic to do, since comments do not have a unique id. Though if someone finds a way to implement this it would be accepted

[tiwarys]

@Stypox
I think this information might be useful.
We can highlight any 1 comment at a time in YouTube website by clicking on the timestamp. See this video. After clicking on timestamp of any comment in a video some ID is being generated.