Add definition of new DwC terms

[CecSve]

Feedback on API SQL Downloads (Github source for this page)

In the Full list of available SQL column names dropdown, caste does not have any definition but should be included as it is now accepted as a DwC term: https://dwc.tdwg.org/terms/#dwc:caste. Check and update:

• [ ] caste
• [ ] materialentityid
• [ ] materialentityremarks
• [ ] verbatimlabel
• [x] eventtype
• [ ] superfamily
• [ ] tribe
• [ ] subtribe
• [x] mediatype
• [x] hascoordinate
• [x] hasgeospatialissues
• [x] level0gid
• [x] level0name
• [x] level1gid
• [x] level1name
• [x] level2gid
• [x] level2name
• [x] level3gid
• [x] level3name
• [ ] dwcaextension
• [x] eventdategte
• [x] eventdatelte
• [ ] v_caste
• [ ] v_materialentityid
• [ ] v_materialentityremarks
• [ ] v_verbatimlabel
• [ ] v_superfamily
• [ ] v_tribe
• [ ] v_subtribe