If Marlin is inside the temperature ISR, the stepper ISR is enabled. If
a stepper event is now happening Marlin will proceed with the stepper
ISR. Now, at the end of the stepper ISR, the temperatre ISR gets enabled
again. While Marlin proceed the rest of the temperature ISR, it's now
vulnerable to a second ISR call.

Also lined up the >> 1 and / 2 mentioned earlier in the unconstrained I term issue,

Also improve the documentation of this and related options, and set
EXTRUDE_MINTEMP to 170 everywhere.

`FORCE_INLINE` seems to have no effect on code generation with standard
optimization.

So that `ultralcd.cpp` doesn’t need to worry about the details.

Follow-up the PR #3643(Temperature singleton)

・Change from fanSpeedSoftPwm[0] to thermalManager.fanSpeedSoftPwm[0] in planner.cpp
It fix compilation error when FAN_SOFT_PWM is enabled.

・Remove declaration of setExtruderAutoFanState() in temperature.h
Because that function was abolished.

・Change from babystepsTodo to thermalManager.babystepsTodo in ultralcd.cpp
It fix compilation errors when BABYSTEPPING is enabled.

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

As noted by @FalloutBe in #3519

Following up on #3231

Fixes for #3189

Setting a temp is still missing

Adds the parameter U to M303. If U1 is included , it will use the
PID-values from the auto-tune.