Remove Path from group of supported types of items for domain detectors

[robertbartel]

Note that this issue requires #566 to be complete first.

During the review of #566, it was suggested (here, here, and here at least, and possibly elsewhere) to remove Path from the group of possible types for items examined by ItemDataDomainDetector objects. This seems like a solid idea but will have some further implications and considerations (e.g., should we do the same for bytes?). As such, that task is receiving this issue of its own.