Add an option to define q values in the input parameter file as angstrom or nm

[MarcBHahn]

It would be very handy to have an option to tell McSAS if the q values are provided as nanometer or Angstrom.

[toqduj]

Agreed. Unit settings for input and output could be in a separate configuration file, or unit setting for input in the data read-in options, output will then default to SI, or at least nm and 1/m.

[MarcBHahn]

Having these options in the "read_config_nxs.yaml" would make sense in my opinion.

[toqduj]

linked to #9