Add more flexibility for minimum ground speed

[MrD-RC]

This PR adds more flexibility to minimum ground speed. Access has been added to the programming framework for retrieval and override. An example use would be setting the min ground speed to be x km/h above the wind speed.

• Added overriding min ground speed to the programming framework.
• Added reading min ground speed to the programming framework.
• Updated nav functions to get the min ground speed via the programming framework. This handles if the override is enabled or not.
• Added min ground speed element to the OSD. This involved re-formatting osdFormatVelocityStr to take a osd_speedTypes_e value. Instead or adding another Boolean to define speed types. Moved Airspeed variants in to the function too. I think it's a neater and more futureproof solution.

Requires Configurator https://github.com/iNavFlight/inav-configurator/pull/2382

Todo

• [x] Add getting wind speed to programming framework
• [x] Add getting wind direction to programming framework
• [x] Configurator side
• [ ] Test