Investigate driver controlled pseudo-velocity mode

To make it easier to control the robot, it could be useful to create a velocity based drive mode. It's difficult to create a drive mode that responds to driver input, but it may be possible to create a way to create a mode that drives the robot at a velocity that is proportional to controller input.

[This paper](https://www.chiefdelphi.com/t/paper-frc-drivetrain-characterization/160915) describes how to make drive the robot in this way.

- [ ] Mode to drive using voltage-intercept, kV (and maybe kA)
- [ ] Integrate these into velocity based closed loop modes
- [ ] Drive mode that can be run to calculate voltage intercept, kV, and kA