Make use of TaxonomicStatus field from DarwinCore to determine taxonomic status when possible

[dimus]

From v1.2.0 isSynonym is deprecated and substituted with TaxonomicStatus field, that, I think, better reflects meaning of the name according to the data source.

In https://github.com/gnames/gnverifier/issues/94 @Adafede shows that TaxonomicStatus can be useful to find out fine-grained taxonomic meaning. I want to try to harvest this field, from DwCA files and try to make normalize values that people put into this field.