Merge topic 'depth_map_bits'

ea5c8559 Update the baselines for depth render to image tests
c0119596 Warning message about the use RenderToImage mode
bd4ba00f Clear to a transparent white background in RenderToImage mode
d6e63c64 Revert "Remove unnecessary depth buffer attachment for RenderToTexture"
99316df2 Use depth image scalar type for render to texture mode
4679780d Added superclass API for depth image type
169d03f4 Remove unnecessary depth buffer attachment for RenderToTexture

Acked-by: Kitware Robot <kwrobot@kitware.com>
Merge-request: !1456