Wifi handling needs fix for Tello TT and Open Source module

[jsolderitsch]

In types.py there are lines:

class ControllerHardware(Enum):
    TELLO = 'TELLO'
    OPEN_SOURCE = 'RMTT'

In fact if you connect the new Open Source Module to the Tello, the default wifi prefix starts with RMTT.

But the wifi startup logic breaks because there is a hardcoded string in tello.py:

    _wifi_ssid_prefix = 'TELLO'

There needs to be some way to allow the ssid prefix begin with either TELLO or RMTT.

Not sure what the best way to achieve this might be.

Since the Mac platform does not implement the wait for function, then the code examples works even with the new Wifi access point name pattern.