Support for other custom embedders like flutter-pi and ivi-homescreen

[payam-zahedi]

For now, we are supporting only the Flutter Linux GDK embedder that is part of the flutter SDK.

But, It's also possible to connect the Flutter in the Host Machine (Your laptop) to other custom embedders in your remote machine (Raspberry Pi).

• [x] flutter-pi by Adrera
• [ ] ivi-homescreen by Toyota
• [ ] flutter-elinux by Sony