add description fields in EML Coverage sections

[sformel-usgs]

Currently Geographic Coverage generates a bounding box, which is nice but doesn't give the option to include a human-readable description via the EML term geographicDescription, like the IPT does. Adding this would be an easy way to make the metadata a little more useful. See screenshot from this dataset for example:

https://ipt-obis.gbif.us/resource?r=marine_cbs_swath_surveys#anchor-geospatial

[sformel-usgs]

Doing the same thing for taxonomy would be useful. For example, being able to describe taxa as "reef fish" can sometimes help a user understand a long list of latin names.