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. 
I think we can convert this and similar methods to dictionary(-ies):
```ruby
true_false_hash = { 'Y' => true, 'موجود' => true, 'N' => false, 'متوفى' => false }
true_false_hash['Y']            # => true
true_false_hash['متوفى']        # => false
true_false_hash['55']           # => nil
```