RIP 602 - Prusa MK3 Extruder Upgrade (R3 edit)

Issue 602: it is excessive inconsistent extrusion on MK3 and MK2.5, it creates a slight basket weave on all prints or wont extrude at all after retracting or doing circles; quite noticeable on layer heights at 0.3mm and round objects.
There is some variation with 602 user to user and many of these issues have similar looking results such as over extrusion can be easily mistaken for 602 issue.

Goal was to copy all things about MK2 extruder and apply to MK3 while still using MK3 parts.

Airf