Fix #8710

* Merging early because of build failures.  See #8105

* Make LPC1768 pinmapping not specific to Re-ARM

* Add HAL_PIN_TYPE and LPC1768 pin features

* M43 Updates

* Move pin map into pinsDebug_LPC1768.h

* Incorporate comments and M226

* Fix persistent store compilation issues

* Update pin features

* Update MKS SBASE pins

* Use native LPC1768 pin numbers in M42, M43, and M226

Alternative to #7882. If F_CPU is greater than 1000 it can be evenly divided by 8. Over 10000, 16; over 100000, 32; over 1 million, 64; etc.

Replace ARDUINO_ARCH_AVR with __AVR__ to better detect architecture for non-Arduino dev environments.  Resolves compile failure in PIO for 8-bit Teensduino targets

More info:
https://forum.pjrc.com/threads/33234-Using-Teensyduino-Selecting-Teensy-3-2-3-1-board-has-incorrect-platform-define
http://www.atmel.com/webdoc/avrlibcreferencemanual/using_tools_1using_avr_gcc_mach_opt.html

Implement AVR Platform

The extrusion speed was wrong due to a not high enough precision of
esteps to XY steps, therefore now the target float values are used to
calculate the ratio between XY movement and extrusion speed.
The e_speed_multiplier8 was replaced by an absolute multiplier called
abs_adv_steps_multiplier8, therefore one multiplication and bitshift can
be saved inside the stepper ISR. Due to this, also extruder_advance_k is
better suited inside the planner and not the stepper files any more.

.) long to int: Extruder stalls at 10kHz / 20kHz step limits with long.
.) Take the delta_adv_steps calculation out of the step_loops loop. Wasted calculation performance if done inside.
.) >> 2 replaced by 3: Is divide by 8. Reason: Timer 0 runs at 16/8=2MHz, Timer 1 at 16/64=0.25MHz. ==> 2/0.25=8.

We should use `constexpr` wherever it makes sense, for its added benefits. See http://stackoverflow.com/questions/13346879/const-vs-constexpr-on-variables

Probably needed for long straight lines when using high microstepping