3DLabPrint Piper Pawnee (Dusty) motor mount

Reinforced motor mount for the 3DLabPrint Piper Pawnee.

Provides the following features:

- Using the original SK3 (3542) metal motor mount plate for reinforcement
- Cooling channel for the motor (a skirt around the motor to keep airflow close to motor vent holes), which also increases the strength of the motor mount plate.
- Small gap at the mating surfaces between the motor mount and the fuselage. A CA glue can make a very strong bonding by filling that small gap (instead of filling a q