Create more beautiful player page, when no stream is running or live

[saschafoerster]

Is your feature request related to a problem? Please describe.
I open up my player page, and when the streams are not running it looks pretty broken, as images just don't load...

Describe the solution you'd like
I would prefer to have images, that show clearly, that the stream is not running, but not broken images that the browser doesn't load.

Describe alternatives you've considered
Maybe the last stream-image should be used with an overlay saying, that the stream is offline right now...

Additional context