x & y endstop bracket for Alunar 506. Fixes inaccurate "auto home".

Just assembled the Alunar 506, one of the many budget Prusa clones. When I first reverted to the home location, it was not even near the bed. It was about 10mm off of where it should be in both directions.

These mounts are exactly like the factory ones, except the switch mounting holes have been shifted 10mm from the original locations. The auto home location now sits 6.3mm past the edge in the X direction and 10.2mm past the edge in the Y direction (to compensate for the leveling screw). Qu