inputs/.TNRS/schema.sql: taxon_match."__accepted_{genus,specific_epithet}": renamed to "__accepted_{genus,specific_epithet,infra_{rank,epithet}}" since this now includes these other ranks as well

bugfix: inputs/.TNRS/schema.sql: taxon_match."__accepted_{genus,specific_epithet}": use "*Accepted_name" instead of "Accepted_species[_binomial]__@TNRS__@vegpath.org" (from "*Accepted_name_species") because Accepted_name_species apparently sometimes does not match the Accepted_name and uses malformed Unicode characters

backups/README.TXT: added backup retention policy

bugfix: schemas/util.sql: derived_cols_export(): also need to first run util.derived_cols_remove() if changing the derived column order

schemas/util.sql: added derived_cols_remove(), which allows derived columns to be re-created in a different order

schemas/util.sql: added drop_derived_col(), which ensures that drop_column() only cascades to views

fix: schemas/util.sql: drop_column(): also need to recreate dependent views

schemas/util.sql: added drop_constraint()

inputs/.TNRS/schema.sql: taxon_match: `inputs/.TNRS/data.sql.run refresh`: documented runtime (1 min)

bugfix: inputs/.TNRS/schema.sql: taxon_match: use "Accepted_species[_binomial]__@TNRS__@vegpath.org" instead of "*Accepted_name_species". this fixes a bug in __accepted_infraspecific_label where Accepted_name_species with trailing whitespace could not be prefix-removed from names that contained just a species binomial.