X2 Elf hardware kit

A hardware set for X2 Elf frame. See the [rotorbuilds page](https://rotorbuilds.com/build/9868) for more details and pictures.

The camera pod is tested to fit Runcam Micro Swift and Runcam Micro Sparrow. The Swift is longer than the Sparrow, so there will be even less clearance for the stack because of the connectors at the back. The camera uptilt is 25 degrees. The pod gives enough clearance to run 2 inch props, e.g. Gemfan 2035 four-blades.

Update: alternative Runcam Micro Swift/Sparrow