Add tracks from other sources to the search list

[Lumluk]

Since Spotube is connected to Spotify, the track listings are the same as there, although the tracks are played from other sources. There are situations where a song is not on Spotify but it is on YouTube, my idea is to include search results from other sources in Spotube searches so people can enjoy whatever tracks they want.

UPD- I've also noticed an issue where when an original track is in Spotube connected to Spotify but the original of that song isn't on a third party source, in this case YouTube, then a remix or cover is included instead of the track you want to hear.