See https://github.com/MarlinFirmware/Marlin/issues/14745#issuecomment-538781253

Changes only affect UBL.  Everything else is left alone.

- Move FWRETRACT to the planner
- Combine leveling, skew, etc. in a single modifier method
- Have kinematic and non-kinematic moves call one planner method

Better encapsulation and considerably reduce stepper jitter

Use macros that explicitly avoid double-evaluation and can be used for any datatype, replacing `min`, `max`, `abs`, `fabs`, `labs`, and `FABS`.

Co-Authored-By: ejtagle <ejtagle@hotmail.com>

* Automatically reset stepper timeout in manage_inactivity

Any code that adds moves to the planner can skip resetting the stepper timeout. We can let `idle` / `manage_inactivity` reset the timer whenever it detects any moves in the planner.

* blocks_queued => has_blocks_queued

The updated planner takes the length of the move, so this pre-calculation is no longer needed.

Fix #9482

set_destination_to_current() changed to set_destination_from_current()

set_current_to_destination() changed to set_current_from_destination()