Refactor getSimilar to use Lucene for 3 names

The getSimilar method contains an if block that deals with names that have three parts (equals to three spaces).

See here: https://github.com/openmrs/openmrs-core/blob/720fe1c5cfd189ad572e4245c4248f65819b433f/api/src/main/java/org/openmrs/api/db/hibernate/HibernatePersonDAO.java#L116

I spilt up the refactoring to make smaller changes in one PR. 

The discussion can be found here: https://talk.openmrs.org/t/soundex-search-in-lucenequeries/26068/34?u=fruether