Log whether homing with probe or endstop

Add note suggesting RAMBo users use the RAMBo board type or platformio environment

Cleanup of pins files, Conditionals

Add note that Viki 2.0 wiring diagram v1.2 has a mistake in it;

Suppress warnings

Repair MarlinSerial with TX-buffer

These '{' are important to avoid the redefinition of `unsigned char _sreg = SREG;`
at the same level.
Used in
```
#define CRITICAL_SECTION_START  unsigned char _sreg = SREG; cli();
```

Update french language

MIN_SEGMENTS_FOR_MOVE => MIN_STEPS_PER_SEGMENT

Follow-up to #4666

M211: Enable/Disable Software Endstops

PREVENT_DANGEROUS_EXTRUDE => PREVENT_COLD_EXTRUSION

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

Clean up ultralcd code, dependencies on ULTIPANEL

dropsegments => MIN_SEGMENTS_FOR_MOVE

Optimize, reduce size of MarlinSerial

Fix_Zig_Zag

Improvements to homing / leveling

Add Rambo support/env to platformio.ini; properly maps extended pins

extruder_multiplier => flow_percentage