Have pelican plugin write `TransferErrorData` with specified errror type

[joereuss12]

Now with #714 in place, we can interpret nested classad list of classads to write to our output file. This way we can populate Todd M's TransferErrorData field with known error types that even condor understands. This should be done after/with #538 so that we can use newly enumerated client error codes for our errors (whether in TransferErrorData or in DeveloperData if not defined by condor.

[bbockelm]

Assigning to Sarthak -- this will require a discussion with Todd Miller (there's also a relevant Google doc he has created with the associated error classifications).