media source data from play() hook is too temporary

[goto-bus-stop]

We only publish the sourceData to the websocket, it is not available in /api/now. this means that media sources that rely on the play() hook don't work if you join while media is already playing, only if you are already there when it advances to media from that source.

I think we can store the sourceData in the history entry and merge it in /api/now, /api/booth, etc