Followup to #14573

* Serial assert (needs work)

* Bring STM32F4/F7 together

* Tweaks to STM32 headers

* More general 'stm32_timer_t'

* Move vsnprintf_P to Marduino.h

Not all scripts answer --help yet. This will be added to 'mfinfo' soon.

Changed the default to overcome the changes in:
5018fdac
This commit exposed a bug because the Ender-2 was using a MINIPANEL lcd
and getting default values that were too low, so the text was too weak.
However, the panel should be MKS_MINI_12864, since it
explicitly sets the correct contrast without relying in the defaults.

Co-Authored-By: Msq001 <msq001@users.noreply.github.com>