MP Post-Release Checklist

[acoffman]

• [x] Remove association of assertions & evidence with variants
• [x] Rename postgres table drugs->therapies
• [x] Activerecord model rename
• [x] Remove logic mapping therapy_id <-> drug_id
• [x] Port field on revisions from drug_ids to therapy_ids (this must happen after the table rename has rolled out to prod)
• [x] Change column name in postgres to significance
• [x] Rename custom icons civic:drug -> civic:therapy
• [ ] Update NDex script
• [x] remove now unused variant columns in postgres (description, score, sources etc)
• [x] Make PR to DGIdb to update the CIViC scraper

Non-MP related: finally do https://github.com/griffithlab/civic-v2/issues/1