materials are too generically named, can conflict when integrating

[ooeygui]

Describe the bug
When the URDF for the Kinect is included in another XACRO, the generic material name can conflict. Suggest namespacing it.

To Reproduce
Create a xacro which defines a material like black.
Include the kinect urdf.

notice that robot state publisher crashes because the URDF parser fails

** Request **
Prefix the materials like azure-kinect-black