Document metadata configuration in more detail

[altmank]

Is your feature request related to a problem? Please describe.
There is not enough information about the metadata generation config file to understand how to configure it for an IFD 8.2 instance.

Describe the solution you'd like
More information in the wiki documentation or helper arguments for the command line.

Describe alternatives you've considered
Not moving forward with using XrmMockup as I can't configure it correctly

Additional context
N/A