No compromises for the manage_heater(). manage_heater() will return immediately when there is nothing to do, but needs a constant detaT to work proper.
Calling idle() only every 200ms results in a display update every ~2 seconds - that should be enough.
For the other functionalities in idle() and manage_inactivity() 200ms is a lot but hopefully works.

Saves about 2669 bytes when deactivated. (About 1% for a AT2560, about __4%__ for a AT644!)

When setting the bed temp via M140/M190 if the thermistor does not read an increase of WATCH_BED_TEMP_INCREASE degrees by WATCH_BED_TEMP_PERIOD seconds then it will throw "Error:Heating failed, system stopped! Heater_ID: bed" and call the kill() function.

Conflicts:
	Marlin/Configuration_adv.h

Following up on #3231

follow-up the commit 7326d63ce0
update Configration_adv.h of Hephestos2
delete unnecessary spaces

Redo of #2939 rebased against RCBugFix

Make stepper shutdown after inactivity dependent on a new set of
#defines.
DISABLE_INACTIV_X
DISABLE_INACTIV_Y
DISABLE_INACTIV_Z
DISABLE_INACTIV_E

And make exemplaric Configuration.
Names can be discussed.

This makes the disabling of the steppers independent from the DISABLE_?
settings witch shut down the steppers immediately.

• Removing trailing whitespace
• Adjusting indention for better readability
• Removing duplicated entries

Analog to https://github.com/MarlinFirmware/MarlinDev/pull/250 by
@RicardoGA

Restore the Babystep Multiplicator functionality and now it's available
for X/Y/Z

only X and Y were not implemented

- `SD_DETECT_PIN` replaces `SDCARDDETECT`
- `SD_DETECT_INVERTED` replaces `SDCARDDETECTINVERTED`
- Revise the description of `SD_DETECT_INVERTED`
- Add a note about the override of `SD_DETECT_INVERTED` in
`Conditionals.h`

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

it's disabled by default

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

Fixed an error where SDCARDDETECTINVERTED was being defined/undefined
improperly

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