Acquire full ligand SDFile for PDBe

We've agreed with Roshan that the best plan for PDBe is not to create 3 total sources for CCD/CLC/PRD in UniChem v3, but to use one single batch SDFile with all PDBe ligands. This currently exists for the set on the main PDB consortium page but not for PDBe. Roshan will take this back to PDBe and we will hopefully hear back when he's made it available. I'm putting a due date on so we can follow up in a couple of weeks if we haven't heard anything. @oboyle I know you were interested in us having this discussion. Sadly he had to go before we could get on to depositor-facing data checking tools, but I can reprise a discussion with another member of the PDBe team.