[discussion] Prefer LTV over Ramsete

[DeltaDizzy]

Currently, the WPILib trajectory stack consists of Trajectory and related classes in addition to the following controllers and helper classes:

• RamseteController
• RamseteCommand
• LTVUnicycleController
• LTVDifferentialDriveController

RamseteController has opaque tuning handles, with those exposed by the LTV controllers being much more understandable at a glace (with the analogies of error tolerance and maximum control effort). Preferring LTV in examples and documentation could greatly improve the experiences of teams opting to do differential drive trajectory following. LTVUnicycleController would be presented as the "basic" option and (subject to discussion outcomes) a premade command type create for using it. LTVDifferentialDriveController would be presented as a more advanced and better UX option for teams who are comfortable with SysId and creating custom commands. frc-docs and examples changes would accompany this. Ramsete would not be deprecated but documentation would recommend using LTV instead as there are few if any advantages to it.

[calcmogul]

We've actually discussed deleting all controller command classes, because they're more error-prone than just using the controller directly.

[DeltaDizzy]

That was met with much debate (#3350, #3366, #5352), so I guess consider this attempt 4 at a consensus :p? The main focus here is the effective replacement of Ramsete with LTV, regardless of the deprecation of all the controller commands or not. I just included that to say that if RamseteCommand or something like it is to be retained, a command using LTVUnicycleController should be provided as its replacement, be it more like RamseteCommand or the proposed TrajectoryCommand.