Add search in playlists

• [✅] I carefully read the contribution guidelines and agree to them.
• [✅] I checked if the issue/feature exists in the latest version.

I use newPipe primarily to listen to music which is why I usually only use it as a media player.

I have playlists with hundreds of songs in them and I thought it would be awesome and pretty trivial to add a search in playlist button or something so that you could find your songs and start the playlist from there easily.