Clearpath Dingo bumpers

Bumpers for Clearpath Dingo to protect the wheels from the environment and vica versa. Print for one each corner, two of which should be mirrored in the slicer.

Needed for mounting:
- 4x M5x60 sunk head socket screws to replace the ones where the horizontal tab mounts in the middle.
- Also recommended are 8x m5 flat washers to put under the two locknuts on each inside cornertab.