Use model for required fields

[orangewolf]

Story

#130

Expected Behavior Before Changes

Any model with out a year was throwing an error

Expected Behavior After Changes

Only throw an error on the year if the year is required

Notes

Asking Christi this question:

• We validate the format and year fields. If the field is required on a work type and it does not match the format we through an error. What do we do if it is not required? Do we make it blank or do we still throw an error on that records import?