Find similar descriptors

Add a function that for selected input Descriptor (in @RequestBody) will return a ranked list of similar existing Descriptors in the database.

Use a similar approach as for accession similarity, but:

1. title, description string similarity
2. columnName, uom
3. category
4. crop
5. minValue, maxValue can be ignored
6. compare descriptor.terms by code, title, description
   1. find the codes of descriptor A that match a code in descriptor B
   2. each match adds points to the score