Minimal MK7 folgertech extruder remix

This is a remix to use the folgertech bearing. I added a revision 2 which might make it easier to put the bearing in. I added revision 3 it removes the bottom of bearing mount to make it easier to remove supports and install bearing. I added a revision 4 which adds an inset to one screw hole on the bearing holder. i added 5 and 6. 5 adds a support. 6 adds a swivel for the bearing center and enlarged bearing screw inset.