Add an option to prefer gstpay over decoder + raw payloader.
Rewrite the autoplugger a little so that it prefers to plug demuxers and parsers before payloaders.
Rework the way we pass data to the autoplugger. When we have raw caps, plug a converter element to make pluggin to raw payloaders more successful. Make sure all dynamically plugged payloaders have a unique payload types.
Make a factory that uses uridecodebin to decode any uri and autoplug a payloader when we have one.
