Fixes #13410 and redeclaration of `BUTTON_EXISTS`

According to #13397

Reference: #13380

See https://github.com/pinchies/Marlin/pull/1#issuecomment-471388743

See commentary at #11623

* Multi-nozzle selective duplication
* Use a bit-mask, reduce stepper_indirection.h size
* Tweak the multi-nozzle duplication description
* Use 'S' as a bool in M605
* Add HAS_DUPLICATION_MODE conditional
* Remove '_MODE' from the option name
* M605 in the style of Stacker M280
* Also include direct mask style (P)

As mentioned in #13370

The chances of a 10° overshoot is pretty minimal.

Originally #13344

Add support for printers with inverted fan pins by adding `#define FAN_INVERTING 1` to `Configuration_adv.h` and modifying the fan write macros.

Should fix "spontanous heating" problems due to order of operations error. Error occurs at least with ststm32 v5.1.0 in PlatformIO.