Added AP_EFI_Serial_FH driver, changed AP_EFI and config to accommodate new driver

[gonzoveliki]

Dedicated serial driver for getting telemetry from EFI Fly Henry. https://www.[flyhenry.cz/images/navody-pdf/engine-management/Engine_Management_Manual_260_Fly_henry1.pdf It is still in development, I have to map and scale all readings thoroughly. It's not breaking anything... tested with CubeOrange+

[peterbarker]

Ping @gonzoveliki this is awaiting rework.

[Hwurzburg]

@peterbarker aren't we doing LUA drivers instead of C++ drivers now for EFI?