Add description for Confidence stream type
Add description for Confidence stream type

Change-Id: I1accb9e232949d1b2137a4570fcd5e043e9d4aab
Signed-off-by: Evgeni Raikhel <f85458431d26324487c02be81bf1e902412cb12e@intel.com>

IntelRealSense/librealsense,IntelRealSense/librealsense,IntelRealSense/librealsense,IntelRealSense/librealsense,IntelRealSense/librealsense,IntelRealSense/librealsense,IntelRealSense/librealsense,IntelRealSense/librealsense,IntelRealSense/librealsense