3 new features

[piscopancer]

1. song progress is remembered, it starts from the timestamp on reconnect. With different internet speeds songs download differently, so it will help players sync at exact timestamp.
2. cache music on server & client for some time, like a week.
3. pause music after dropping the jukebox + hotkey to pause music. Unpausing uses the 1st feature 👆

Please guys upvote this issue to get author's attention