Added metadata entry for AICs

refs #5823

Create AIC redirects to metadata entry page.  Added new form for Dublin
Core metadata for AIC that doesn't have Part of AIC, potential for more
divergent behaviour.  MicroServiceChainLink is started once metadata is
saved.  Cleaned up Dublin Core forms to be a ModelForm.
ElasticSearch doesn't index processingMCP.xml

refs #5803

Put a filter in ElasticSearch functions to prevent processingMCP.xml from
being indexed.  Other paths use the METS file to find the files to index,
but the AIC METS file is in metadata/ not /.

Removed unused code, cleaned up imports, fixed removing tmp directories on
DB recreate.
Fixed problems with AIC MicroServiceChainLinks

refs #5823

Added create METS.xml script to AIC chain.  Fixed createMETS file to not
bail if objects/metadata/transfers does not exist.

Updated bagit script to check that all the payload files/folders existed.
Added metadata/ folder to the bagit payload so the AIC METS file is
included.  Cleaned up bagit script.
Added isPartOf to METS file

refs #5803

Renamed Part of AIP to be isPartOf, like Dublin Core name.  Updated Dublin
Core metadata section in create METS.  ElasticSearch should index all
the fields in the METS file, including the new isPartOf.