Come up for routines for cleaning up database following API runs...

[TJGorrie]

• API should delete all ligands on disk prior to running
• API generates new ligands
• pipeline checks for ligand/Fragalysis_ligand existence
• If files are not found, delete them!

[TJGorrie]

We don't have to worry if the ligand is repopulated - it is considered a new ligand and will need independent review...

Alternatives could include disabling to ligand from view. but this would lead to consistency problems...