Resolve "Corrections - create a Hawdon method with selectable Rc"

Issue being addressed

This merge request Closes #60

Implementation Details

Updated the Hawdon incoming intensity method to make sure that a user can select which reference monitor to use. The reference monitor GV can be given in the SiteInformation (YAML or manually entered). It's in SiteInformation as this might be difference for different sites.

For now I've written it so that a user gives the actual GV value in SiteInformation - a future update could be that a user gives the NMDB code (e.g., JUNG) and we have a look up table to prepare this, but Lasse mentioned this number could change depending on when the cutoff rigidity was calculated. For now user provides the number.

If no number is given it defaults to use JUNG (4.49 GV).

I've also updated naming in ColumnInfo and SiteInformation to be clearer.

Tests included.

Related Issues

Review Notes

• Double the names in ColumnInfo and SiteInformation are good

Merge Request Checklists

• Code follows project coding guidelines.
• The issues acceptance criteria is met.
• Documentation reflects the changes made.
• I have covered the unit testing.