Improve BLTOUCH_HEATERS_OFF functionality

I think I forgot to Sync before I committed last time.   Some UBL
changes did not stick.

Also, update the gMax configuaration.h file so other than unique numbers
and settings, it exactly matches the default configuration.h file.

* Restore LSF functionality

Some of the typo's persisted...   Hopefully this gets them all fixed.

* Restore user's expectations of how G28 should behave

* Allow Nozzle size control with ornery host programs

 - rename to PROBING_HEATERS_OFF
 - move heater pausing functionality into thermalManager
   - add variables, pause(), ispaused(), other functions
 - add fan pausing functionality -> PROBING_FANS_OFF
 - add probing_pause() wrapper
 - move pausing into do_homing_move() and do_probe_move() to minimize quiet time and so other probe types can benefit
 - example configs

G29 P1 stops reporting Invalid location with this patch

Support temperature units in M503

UBL Clean up.

- move platformio.ini out of source directory to be more consistent with 'normal' PlatformIO usage
  - facilitates IDE integration
- add related .gitignores

Update git helper scripts, config comments

Fixed USE_CONTROLLER_FAN #define usage

also removed wayward 'address of' ampersand in setTargetHotend and setTargetBed parameters

Fix broken fwretract recovery extruder feedrate

When both lowering and recovery are performed using the same "prepare_move_to_destination()" the extruder recovery feedrate ends up being ignored and, instead, is only capped by either the maximum e-speed or the time it takes to perform the z-lowering. 
Performing the two moves separately from each other ensures a correct recovery feedrate.

Add EXTRAPOLATE_BEYOND_GRID option to bilinear leveling

Shutdown heaters, autotemp on SD Cancel

Compact smart_fill_mesh slightly

Noted in #6550

Further cleanup of UBL

Implement USE_CONTROLLER_FAN as a feature