Add chromecast/google cast support

[ippocratis]

Well thats tricky as idk how Foss you want to keep the app
cast is cool to have to send media on the big screen but it is a proprietary google protocol
Also idk how hard it is to implement

[savvasdalkitsis]

I'm not that fussed about pure foss tbh. I had this in the back of my head an an option so this is definitely one for the blacklog