add mimetype support

[yocontra]

for instances where you cant control the URL, it should support defining a mimetype in the source like every other player does

[flavioribeiro]

I agree we should receive the MIME but I don't know if we should check for it inside the method. It seems that RTMP doesn't have a mime (I assume it's because it's actually a protocol not a format?).

[yocontra]

@flavioribeiro Doesn't have one, but seems most people have accepted rtmp/mp4 as the defacto "mimetype".

Really just trying to make this possible:

new Player({ source: 'something.com/anything?vid=something', mimeType: 'rtmp/mp4' })

I have to wrap the URL in a forwarder to make it work on an https site (new default chrome CSP crap), so I lose extensions and protocols and canPlay returns false.

Until now I've been doing this:

const orig = ContainerFactory.prototype.findPlaybackPlugin
ContainerFactory.prototype.findPlaybackPlugin = function (source, mimeType) {
  return orig.call(this, unwrap(source), mimeType)
}

where unwrap deconstructs the URL from the forwarder to the original.