Centralised beep code to lcd_buzz().
From gcode_M300() and lcd_quick_feedback().

Enforced max. duration for M300 to 5 seconds.

Corrected description in 'Configuration.h'

LCD_FEEDBACK_FREQUENCY_HZ 0 gives now a silent delay of
LCD_FEEDBACK_FREQUENCY_DURATION_MS.

Introduced in commit 697ee2dc and later spread to other files.

- Replace “Mendel” with “RepRap”

The line const bool Z_PROBE_ENDSTOP_INVERTING = false; // set to true to
invert the logic of the endstop is in the main configuration.h but
wasn't present in the example configuration.h's. Causes a compiling
error with Z Probe enabled. Just added it to all the configs. :)

- Sections in all `Configuration_adv.h`
- Recognize JAPANESE/WESTERN/CYRILLIC options
- Better capturing of comments for tooltips

- Addressing issue mentioned at #1699

Don’t set CUSTOM_M_CODE_SET_Z_PROBE_OFFSET if there’s no Z probe

make it unconditional
remove all definitions in the 'Configuration.h's
remove form 'Conditionals.h'

- `Conditionals.h` is included twice, setting LCD values the first time

- Add `Conditionals.h` with calculated configuration values
- Add `SanityCheck.h` with checks for configuration errors
- Remove equivalent code from all configurations
- Move error checks from some sources to `SanityCheck.h` also
- Fix initialization of count_direction in stepper.cpp