Change to Third Party part policy

[Orion Pobursky]

I only have 2 third party parts submitted:
- Raspberry Pi (including HAT): https://library.ldraw.org/tracker/34978
- Mabuchi Boat motor: https://library.ldraw.org/tracker/31095
the Raspi itself is licensed under CC BY-SA 4.0 (and i only used the physical dimensions)
https://www.raspberrypi.com/licensing/
the Mabuchi motor is very old and discontinued (although it got carried over by Tamiya)
do we need to ask them? (to ask Mabuchi @Takeshi may be the better one)

I'm not going back and deleting a bunch of parts. As stated, this will be the policy going forward.