Flight controller stack adapter (30.5mm <--> 20mm)

This is a fully customizable adapter that will allow mounting 20mm components in a 30.5 mm stack and vice versa. You can choose to have integrated standoffs on the top and/or bottom of the 30.5mm and/or 20mm holes. If you choose to have integrated standoffs on the bottom, it will automatically split the file in half so it can be easily printed without supports. You can override this if you REALLY want the STL as one piece and you want standoffs on the bottom.