As suggested in #2521
- Move `ABORT_ON_ENDSTOP_HIT_FEATURE_ENABLED` because `SDSUPPORT` is
also required.
- Add a note that endstops must be enabled for the feature to have any
effect

A speaker needs a AC or a pulsed DC to make a sound, a buzzer only needs a DC.
A buzzer has it's own resonator. It works in most cases to feed the buzzer with a pulsed DC, but the sound will not be as loud as with pure DC.

There seem to be boards where the BEEPER-pin is not able to handle a PWM. Obviously intended for a buzzer.
To make these board able to handle a speaker

* replace the PWM based tone()-function again with a on-delay-off-delay loop.

Hopefully the last time I touch the beeper code.

Just set up the pin. Don't move to a random position.

Simplify servo::move()
* servo::move() does not need the pin parameter - The pin is set during servo_init() with attach().
* servo::move() does not need a return value.

SERVO_LEVELING is the wrong condition to deactivate the servos.

Remove some temporary (Servo *) variables.
SanityCheck for the servo indexes.

Also clean up some trailing spaces in a few other sources

it's disabled by default

#defining something just to define something else doesn’t
make sense

If you want SDCARDDETECTINVERTED, just define it yourself.

If the previous code was intended to define, undefined and then again define the term, that code is improper.

* all Configuration_adv.h: Add #define FAN_MIN_PWM for slow fan stopping
issue
* for K8200: uncommented with tested (and working) values

Updated all the example Configuration.h files for the new display type.

Minor wording correction.

- Make thermal protection for all hotends and/or bed into simple
switches
- Now enable `WATCH_TEMP_PERIOD` when `THERMAL_PROTECTION_HOTENDS` is
enabled
- Move detailed thermal parameters to `Configuration_adv.h`
- Add sanity checks to warn about old configurations
- Change `WATCH_TEMP_PERIOD` to seconds instead of milliseconds