Allow data isolation for parallel tagging of multiple tracking data files with a same tagger
Problem: If a tagging backend is executed in parallel, conflict may arise as the raw, interim and processed data directories are shared.
Proposal: Instead of relying on the model instance name to generate subdirectories in the various data directories, we could use a temporary name. This is to be handled primarily by TaggingBackends, but the exchange protocol is to be updated, so that paths to the input (raw) and output (processed) data directories are communicated.