This patch adds a new system preference PatronDuplicateMatchingAddFields
to list the patron's attributes to use for deduplication.
The default value is surname, firstname and dateofbirth to keep existing
0. Apply the patch and execute the update DB entry
1. Create a new patron with surname, firstname
2. Create another patron with the same surname, firstname values
=> Confirm you get the duplicate warning
3. Modify the syspref to edit the list of attributes used to dedup
4. Repeat 1 and 2 with different values and confirm that you get the
behaviours you expect
Note: This is only impacting the add patron form from the UI, not the
import patrons tool.