Merged nara-schemav3 with master

Mapping fixes
    -Added extent_transform
    -Added subject_and_spatial_transform
    -Added type_transform
    -Moved transforms that require multiple originalRecord fields
     outside of *_TRANSFORMER to prevent multiple runs.
    -Removed contributor
    -Updated is_part_of_transform
    -Removed move_dates_to_temporal
    -Added a collection transform
    -Set Record Group as collection in poll_profiles
    -Removed enrich_date, enrich_temporal_date, and
     contentdm_identify_object from NARA profile
    -Updated date_tranform and is_part_of_transform
    -Added "moving image" to DC_TYPES in enrich-type module
    -Added blacklist=None to def process_arc_all
    -Mapped subject, description, type, and isShownAt

Updated arc_group_extraction to account for both list and dictionary
instances.

    -The items are now appended to a file whose name include the collection
     id, which is then read and inserted into the collection dictionary
     prior to enrichment.
    -The collection label field is set as its title and added to COLL
     since NARA does not include collection enrichment.

Gather ARC collection info from Item file only.

    The collection metadata is gathered only from the item, rather than by
    searching for and parsing the Series file. The item _id is first set,
    then select-id sets the id as the md5 sum of _id. The collection label
    is now set in the enrich module.