Semi-automated PCR deletion workflow

[fluffy-critter]

Whenever double-entry of PCR products happens, the manual cleanup process in the database is a bit messy and sprawling. It would be helpful to have a tool which takes a list of PCR product IDs (either via list or via SQL query), collects a list of everything that would be deleted as a result (pcr_template, additional PCR rounds, gel_lane and associated gels, any now-empty pcr_pools, and pcr_cleanups), shows what will be deleted, and then, upon confirmation, deletes it.