Add support for url parameters as input so it plays automatically

[BdR76]

Is it possible to add support for url parameters as input? That way you can send a song to someone. So I mean something like this to send Happy Birthday

https://bongo.cat/bpm=80&key=113-1-6-5---113-1-8-6

Or something like that. And then it plays your "song" automaticallly, until it's finished or if you hit a key to stop it and play manually again.

[Externalizable]

Related: #155 and https://github.com/Externalizable/bongo.cat/pull/30#issuecomment-735039991