General gz camera

[MarqRazz]

This PR is going to require us to rename the repo gz_camera_descriptions.

This PR splits the repo up into 3 packages:

• One for generic RGB, Depth and RGBD cameras
• One for Realsense cameras (designed to be used in unison with realsense2_description package)
• One for Orbbec cameras (designed to be used in unison with orbbec_description package on the locus branch)
• minimizes dependencies
• updates documentation

[johnsonTyler0511]

Thanks!

[MarqRazz]

Actually I propose we change the repo name to gz_sensor_descriptions and add a note that it currently only supports Cameras but I will add IMU and other sensors when I get a chance.

[MarqRazz]

Hardware tests good 🎉

[forrest-rm]

One question about if we wanted separate example packages for cleaner package dependencies, but everything else are quick changes.