Use EBI-AlpafoldDB API lookup to resolve PAE location

JAL-4660 noted several issues with the new AlphaFoldDB multimer dataset - one other aspect is that PAE files are also named in a different way to those previously provided.
curl -X 'GET' \
  'https://alphafold.ebi.ac.uk/api/prediction/AF-0000000065982887' \
  -H 'accept: application/json'

is sufficient to retrieve the location of a given entries PAE file as the JSON hash key:

"paeDocUrl": "https://alphafold.ebi.ac.uk/files/AF-0000000065982887-predicted_aligned_error_v1.json",