Raspberry Pi camera mount bottom screwless

Remix of [Dwiekawki's Raspberry Pi camera mount](https://www.thingiverse.com/thing:3809015) which is itself a remix of [Nitrocubane's Raspberry Pi camera mount](https://www.thingiverse.com/thing:3747437). It attaches directly to the frame instead of needing M5 screws or nuts. Home Depot doesn't have them anyway I checked.

I've included the top and middle part as well but those are unchanged.