Investigate using Orbbec Femto cameras

[jackjansen]

We should add support for the Orbbec cameras. Especially the Femto Mega, but if possible also the Bolt.

Current plan is to do very preliminary tests with the Orbbec K4A-compatibility layer, and then switch to their own API.

I've created this issue mainly so we can record links to interesting resources.

[jackjansen]

Here is a very detailed comparison of the Femto Bolt to the Azure Kinect: https://github.com/IntelRealSense/librealsense/blob/master/doc/distribution_linux.md

On first reading it makes me think we shouldn't bother with supporting recording/playback with the K4A compatibility wrapper, and maybe we also shouldn't try multi-camera setups with it.