wifidisplay: Use ExtendedRemoteDisplay to launch Wifi Display.

- RemoteDisplay class is used to launch WiFi Display
  implementation in the Android framework with a discovered peer.
  There is a need to support proprietary implementation of wifi
  display instead of the framework implementation.

- To enable this support, ExtendedRemoteDisplay is added,
  which launches the proprietary solution. ExtendedRemoteDisplay object
  is created if the class is available in the package. If the class is
  not available the default implementation will be used by creating
  RemoteDisplay.

Change-Id: I2e2a5e552bc86888848c0402bafd873620b05c21