sql.run_query_into() calls: Use new add_pkey_ param instead of manually calling sql.add_pkey()

sql.py: run_query_into(): Changed add_indexes_ param to add_pkey_ and add just a pkey if it's set. It's no longer necessary to create indexes on every column of a temp table, because the covering indexes for the join columns have been fixed to have columns in the same order as the output table's corresponding index so that they can be used for a merge join.

sql_io.py: put_table(): Add pkey on pkeys table right when it's created, so that any duplicates are detected right away instead of at the end of the iteration. (Duplicates are created as a result of joins matching multiple rows, which often indicates a database misconfiguration.)

sql_io.py: put_table(): Adding pkey on pkeys table: Removed log message because adding an index is considered a low-level operation, which isn't included in the Redmine SQL

schemas/tree_cross-links.sql: Ancestors table: Synced with current definition, which removes unneeded fki_* indexes. Note that the index on ancestor_id might be needed in the future if we ever want to get all the descendants of a plantname/namedplace or perform deletions on plantname/namedplace (which cascade to *_ancestor). For getting all the plantnames/namedplaces (of any rank) for a plantconcept/locationdetermination, though, the *_ancestor_pkey index is sufficient because plantname_id/namedplace_id is the first column in it.

schemas/vegbien.sql: {plantname,namedplace}_update_ancestors(): Fixed slowdown due to removed index on {plantname,namedplace}.parent_id by adding COALESCE to enable using the plantname_unique index for the lookup instead

sql.mk_select() calls: Removed no longer needed start=0 to turn off missing WHERE, LIMIT, or OFFSET clause warning

sql.py: mk_select(): Don't output warning if there is no WHERE, LIMIT, or OFFSET clause, because column-based import has many queries where this is the case and it's annoying to need to specify start=0 to turn off this warning

sql.py: flatten(): Don't sort the input tables by the pkey because it doesn't matter what order the datasource's rows are inserted in. Note that PostgreSQL doesn't guarantee the order of rows in a table, so it is possible that the rows were being inserted in an unknown order before this change, as well.

sql.py: delete(): Cache deletes by default