Update gnd_pos_control and ground_att_control modules

[AmeliaEScott]

Describe problem solved by the proposed feature
The current rover position and attitude control modules are based on fixed-wing control. They work for simple waypoint navigation, but should be updated to account for different types of steering (Ackerman vs. Differential steering) and limitations of rovers. Additionally, rovers behave strangely around edge cases, such as when the navigator module would instruct a fixed-wing craft to loiter, and when instructing the rover to "take off" or "land".

Describe your preferred solution
Research existing control algorithms for Ackerman and Differential steering vehicles, and implement them in the gnd_pos_control and gnd_att_control modules.

Describe possible alternatives
The existing modules implement Ackerman control, so a new separate module could be created for differential steering.

[julianoes]

From call:
@ItsTimmy: differential controller spins in circle when waypoint reached.
@dagar: differential steering rover controller could work like multicopter controller. We could have two controllers, one for Ackermann, one for differential steering.
@julianoes: we can't yaw while going forward as multicopters.

[SalimTerryLi]

Can we add another parameter to determine whether the rover should do in-situ turning or directly move forward while do steering?
I' m looking forward to a solution which can dynamically switch between Ackermann & differential steering. Because I want my rover can have a fluent behavior in wide area but also can easily adapt into limited space. (with the help of RTK)
We can build a simple framework in gnd_position_control at first and then finish the codes for differential steering?
Or, any better ways?

[julianoes]

@ItsTimmy can you make a pull request for this change?

[AmeliaEScott]

I have created a WIP pull request: #12239 . However, this depends upon #11918 , so it must be merged first.