Bug 22046: Simplify and unify the code for get_matches

Bug 22046: Simplify and unify the code for get_matches

To test:
1 - Stage some records for import
2 - Manage the records
3 - Use several different matching rules and note the results
4 - Apply patch
5 - Try several matching rules again and note the results have not
changed
6 - Try under both search engines (Zebra and ES)

Signed-off-by: Liz Rea <wizzyrea@gmail.com>
Signed-off-by: Marcel de Rooy <m.de.rooy@rijksmuseum.nl>
Signed-off-by: Nick Clemens <nick@bywatersolutions.com>