Drop usage of Youtube API for playlists

[jaimeMF]

We can't get more that 1000 items using the api (api documentation), some lists (as reported in #1503) greatly surpass this limit. Switching to parsing the playlist page would solve this, but of course requires more work than using the api.

[Nothing4You]

Maybe you could check how much you can get via api and if it's >1,000 parse the playlist page, otherwise parse API instead of always querying the playlist page?

[JMSwag]

@Nothing4You Might as well use the parser once written, instead of having 2 pieces of code that essentially does the same thing. Minus the fact that the newer implementation will be able to get more then 1000 results.

[jaimeMF]

As reported in #1757 there's one more reason for using the playlist page: private playlists.