Simplify finding accessions

[amhanson9]

Hub has been updated so the path is always parent_directory/status/collection/accession/content and so the collection and accession number formats are more consistent.

Three scripts are iterating through the entire directory (including accession content) with os.walk() looking for markers to indicate a collection or accession in order to allow the script to start at any point. If this becomes too slow, see if we can iterate in a way that stops going down a branch in the directory once it gets to a collection or accession, or if we can add an additional argument to indicate if the start is parent_directory, status, or collection so that the paths can be made without iteration.