LM12UU holder slim with nutholders and bearing stop

I mostly hacked Jonas Kühling work, so all the credits go to him

what did I do?

I converted from LM8UU to LM12UU and from M3 screws and nuts to M4.

I also made the whole thing thicker and put a bigger mouthplate with added nut holders.
It helps me greatly to glue the nut in the nut holder and then just turn the screw.

I also added a small end stop for the LM12UU. As I will use those holders to mount my Z axis in my CNC I thought that maybe the added support is worth the extra pla