Addressing #8676

Example Configuration.h files are not updated yet.   You need to cross
your settings over to the default Configuration.h file in the \Marlin
directory.   (UBL_G26_MESH_VALIDATION enablement has moved to a new
location in the file.)

For parity with bugfix-2.0.x

Move 'lcd_bootscreen()' from `lcd_init()` to 'setup()' where it is cexecute exactly once. Saves 'bool show_bootscreen'.
Move the call of 'lcd_custom_bootscreen()' to the begin of 'lcd_bootscreen()'.
Move the delays into the related functions.
Move the picture loop around 'lcd_kill_screen()' into the function.

Addressing #8166

* auto tune calibration parameters

* solve warnings

* Tweaks to formatting

* review Thinkyhead

* Error

* Initial conflict resolution

All previous items resolved:
- Use of ELAPSED() on timer code
- Switch to use of defer_return_to_status=true as much as possible
- Update & Clean Up of Max7219 routines

* Resolve non-SD case in ultralcd.cpp

set_destination_to_current() changed to set_destination_from_current()

set_current_to_destination() changed to set_current_from_destination()

Based on #7637 by @marcio-ao

Based on #7975 and #7979

Addressing #7745

Added new configuration to inhibit XYZ movements when home is not done