* [New Feature] I2C position encoder support

I plan to continue improving/cleaning this up, as there areas that need work.

* let the cleanups begin.

* progress

* more progress

* comments, rename files, etc.

* clean

* Cleanups per thinkyhead

* a few more cleanups

* cleanups, bugfixes, etc.

* remove unnecessary passes_test(), additional cleanups/optimizations

* cleanups

* misc.

* Fix up I2CPEM.init() and a few other things.

* organize, fix, rename, etc.

* more optimization

* a few more tweaks

Ref #5139

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Configuration_adv.h changes

==============================

add "live" LCD update

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P & S version

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final (hopefully) tested version

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update M115 capabilities print

==============================

Menu changes portion of the requested changes

==============================

changed USEABLE_HARDWARE_PWM from a function to a series of macros

==============================

changes per review

The menu (commands / scripts) is configurable in `Configuration_adv.h`.

- Added conditionals.
- Changed script handling.
- Slimmed and working!
- Added Status message.
- Returning to lcd status screen now!
- Example Configs Updated.
- Cleanups by @thinkyhead

* Unify M600 and M125 pause features
* Cleanup per thinkyhead's comments
* Rename filament_change_menu_response to advanced_pause_menu_response
* Include HAS_BED_PROBE in QUIET_PROBING
* Update gMax example file
* is_idle() is out of scope without the braces
* Convert FT-i3-2020 to Advance Pause names...
* Allow pause even if not printing

- fix broken `M421` due to less-than-careful optimization
- add HOME_AFTER_DEACTIVATE define to advanced config so not everyone has to rehome after steppers are deactivated
- misc. cleanups (remove unused label, unused variables)

- update example configs

add BLTouch-related messages in english and (rusty) french;
add missing endstops.h in ultralcd.cpp;
fix misc. compiler warnings;
fix lsf_reset - ZERO macro can't handle a pointer as it would only memset the size of the pointer, not the size of the entire struct

* relocated ubl state to config. store:
 * removed a number of ubl state variables and padding which were largely unused - saved 58 bytes of both SRAM and EEPROM;
 * modified ubl sanity_check - no longer checks removed state variables that were otherwise unused, where checking didn't seem to accomplish anything, ultimately;
 * removed pre_initialized state, saving 64 bytes of SRAM;
 * removed automatic saving of UBL state after UBL activation/deactivation;
* consolidated multiple GRID_MAX_POINTS_X/Y to 'Global Leveling' section of EEPROM;
* minor update to G29 Sx notes/instructions;
* renamed mesh load and save parameter to 'slot' from 'm' for clarity;

DAC_STEPPER_DFLT wasn't changed to DAC_MOTOR_CURRENT_DEFAULT in all
places on PR #6124

# This is the 1st commit message:

MCP4728 consistency & fix ultralcd.cpp

The MCP4728 DAC controls the stepper motor current strenth on the
PRINTRBOARD Rev F and RIGIDBOARD V2 boards.

PR #5792 on 9 FEB 2017 implemented default drive percentages but only on
the RIGIDBOARD V2.

This change moves the default settings to Configuration_adv.h.

Also, ultralcd.cpp won't compile because of a type def conflict.
Changed it to match the one in stepper_dac.cpp

===========================================================

reword stepper curent section for clarity

===========================================================

change name & improve comments

===========================================================

changed name from A4JP to SCOOVO_X9H per PR #6139

# This is the commit message #2:

fix typo

The offset for Z_DUAL_ENDSTOP (z_endstop_adj) is already in Marlin.
This PR just makes it a configuration item.

z_endstop_adj is initialized in two places so both had to be modified.

Made the double touch portion a conditional compile based on the
PROBE_DOUBLE_TOUCH flag.

==============================================

Bugfix

The current G38 only stopped a move if it involved the Z axis.

Moved all the G38 code to it's own section and put it where it would
always be executed no matter what axis was moving or if the endstop was
enabled.

Also added a comment to configuration_adv to alert the user the double
tap had to be turned on.

==============================================

Change G38 back to using Z_MIN_PROBE

There's no Z_MIN endstop if Z_DUAL_ENDSTOPS is enabled and you have them
set to the top of the gantry.

G38 started out as using the Z_MIN_PROBE pin.  I don't remember why we
changed it to the Z_MIN endstop.

Work around for slicers producing buggy gcode.

As suggested in
https://github.com/MarlinFirmware/Marlin/issues/5570#issuecomment-283059
065