Fix set_lcd_contrast

Cleanup code, organize & document fastio pin mappings

Changed UBL_G26_MESH_EDITING to UBL_G26_MESH_VALIDATION
Added UBL_MESH_EDIT_MOVES_Z to prepare for that change (coming next)

Reference: #6804

Add "live editing" option to LCD menus

Restore current temp accessors to float

G33 updates

Disable PROBE_MANUALLY for UBL

Plus some other UBL tweaks.

Patch LCD code for 5th extruder

Tweak Azteeg X3 PRO _pins.h so Viki2 will work for those without a case light

- add comment explaining that the Panucatt Viki2 wiring diagram uses pin 44

Add `G7` gcode command to move between UBL mesh points

- can be augmented in the future to enable for other leveling systems

Quite simple, but did not want to modify `G1` as the additional checking would slow it down.

Tested & working.

Fix recent regressions, &c.

- fix broken `M421` due to less-than-careful optimization
- add HOME_AFTER_DEACTIVATE define to advanced config so not everyone has to rehome after steppers are deactivated
- misc. cleanups (remove unused label, unused variables)

Fix broken EEPROM save/load

Implement CRC16, develop mesh allocation table

Spindle / Laser support

Update french language

 - Add crc16 utility function
 - Implement CRC16 for config store, remove old checksum, increment layout version
 - Move UBL mesh store/load to MarlinSettings; increment UBL_VERSION
 - Begin to lay out MAT structure, prototype functions, etc.
 - Rename ubl.state.eeprom_storage_slot to .storage_slot
 - Misc. optimization
 - Cleanup/standardize/improve some messages

This is a work in progress!

Separate SWITCHING_NOZZLE and SWITCHING_EXTRUDER

Prevent home_all_axes picking up XYZ parameters from command