Filter: Accession number

genesys-ui#704 (closed) describes that the "Accession number" filter should behave as a string array filter -- accepting a number of entries.

https://gitlab.croptrust.org/genesys-pgr/genesys-ui/merge_requests/686#note_40309

The accessionNumber is indexed as Text due to its length. Perhaps we should allow for eq, contains, starts operators in StringFilter to allow for multiple values.