Yandex.Music Lyrics per MerkD

This extension adds back a sidebar section on Yandex.Music where you can read lyrics of the selected song. It uses the old Yandex.Music database, which is a miracle that it still exists, and has very incomplete coverage.
It is more of a proof of concept and a first attempt at extensions, so it probably has limited use.

You can fing source code at https://github.com/DobriniaMerk/Yandex-Music-Lyrics