Handle adding new multi-word synonyms

Make adding multi-word synonyms in the solr admin automatically update in postgres-solr database and solr index as one word. (if a multi-word synonym is added as two or more words it can cause the proximity search to behave unexpectedly)

This can be done manually right now by entering the multi-word synonyms as 1 word (i.e. firefighter), adding it to the 'multi_word_syns.txt' and 'protected_syns.txt' in solr/cores/possible.conflicts/conf folder and running a data import on the possible conflicts.

Acceptance / DoD:
- [ ] Product Owner advised if task >= 1 full-day, or forms part of the business day
- [ ] Requires deployments
- [ ] Test coverage acceptable
- [ ] Peer Reviewed
- [ ] Production burn in completed