Spreadsheet validation

This is associated with moving inappropriate code out of config/settings.yml which is associated with the upload of orphan spreadsheets (https://osraav.atlassian.net/browse/OSRA-240)
I've created this pull request just to provide visibility of the approach I've been taking, to see if you want me to progress along these lines. 
Note that this will cause several rspec failures, because I haven't updated the tests to align with this module design. 
:+1: for Ruby refinements idea. However, can you not simply pass cell values to these utility methods as arguments instead of modifying Ruby classes in any way?