Logitech C270 manual focus (remix for 0.4mm nozzle)

This is a remix of 2 projects:
* https://www.thingiverse.com/thing:1133080 (for covers only)
* https://www.thingiverse.com/thing:2280016 (focus ring compatible with 0.4mm nozzle)

Support for Wanhao Duplicator I3 Plus: https://www.thingiverse.com/thing:2366995