Explicitly declare insert columns

[mellypop]

To create raptr.bam_tpl_read_group I renamed raptr.bam_tpl_loadable, added the read_group_id column, backfilled it, and dropped the loadable_id column. Previously, bam_tpl_id and loadable_id were the first two columns, so when add_bam_pair_xenocp.py tried to insert using insert into raptr.bam_tpl_loadable values (%s, %s) without explicitly stating the columns being inserted, everything was fine, but now that the columns have moved around, postgres thinks it's trying to insert values for bam_tpl_id and inserted_time because those are the first two columns.

This PR updates the insert statement to explicitly declare the columns being inserted.