Improved documentation around configuration

[rbridgewaterML]

Is your feature request related to a problem? Please describe.

When using Holohub Volume_renderer_xr (Which relies upon ClaraViz), the instructions around setting up the configuration can be confusing.

Describe the solution you'd like

More clear documentation on setting up an initial configuration, and how to tweak the configuration for a particular file to get the desired visual effect

Describe alternatives you've considered

Looking directly at the existing examples and source code can work, but can be more difficult to follow.