Introduce OpenLand_Camera_Depth function

This release is mere a core update & does not interfere with the API.

Here we introduce a new material function called OpenLand_Camera_Depth. It's exactly the same with PixelDepth but it will work with RVT too. It will also take inputs from the OpenLand One-Click RVT tool.

This can be used for integrating OpenLand RVT tools with other landscape materials.