Cleanup: Remove old ways of getting YT dis/likes

[litetex]

• I carefully read the contribution guidelines and agree to them.
• I have tested the API against NewPipe.
• I agree to create a pull request for NewPipe as soon as possible to make it compatible with the changed API.

Some clean/followups after #753; Content

• Removed old way of getting likes (was disabled by YT - as predicted - on 2021-12-13)
• Removed dislike calculation because it no longer works (no average rating)
• Fixes Exception from Could not parse "No Likes" in 0.21.14 NewPipe#7525
• Deduplicated a ton of code inside the StreamExtractor(s) by using default/non-abstract methods
• Fixed tests

[opusforlife2]

I suppose it will have to be a hotfix.

[litetex]

I don't think we have to hotfix this as everything should still work as expected.
However this PR removes the code that by then will be (likely) irrelevant.
So this is just an improvement :)

[opusforlife2]

Oh, I was confused. The calculation method will still work.

[TobiGr]

Looks good.