[Tunein] Fix existing extractors and add playlist (closes #20252)

[blackjack4494]

@biwubo
ytdl-org#20459

@bubbleguuum @betathetatau
ytdl-org#20252

#88

[bubbleguuum]

I created a new PR that applies without conflict.

Note that the conflict was only caused by the files refering to the youtube_dl directory instead of now youtube_dlc
and the fix was to simply get the original PR as a patch file, edit it to replace all occurrences of youtube_dl/ by youtube_dlc/, and apply the patch with git am.

Not sure renaming the youtube_dl folder to youtube_dlc is a good idea for applying original PRs directly.

[blackjack4494]

Don't worry there wouldn't be a problem if the folder was still named without an 'c'. Git seems to be smart enough to automatically identify the minor name change. It's just github that is not able to (at least yet)

I gave it a try earlier and it didn't work for me directly. However the changes you made were good enough just needs a bit more tweaking. No clue whether I already created a branch. But I can show you what I mean then.
One problem or actually the main one was the proper id identification.
The test link could contain to different ids but both of these couldn't be used in making an api request you need the guideId which I started to extract by using regex.
Check it later if I haven't created any branch yet (believe I just have it locally yet). Can also ping you then.

[bubbleguuum]

Note sure what you mean exactly in the second paragraph, but the PR works for extracting TuneIn stream metadata as JSON (with -J).
It doesn't work for downloading audio (does not handle the SHOUTcast stream properly) but I must admit I do not need this functionality so did not test it (until now).