MCPServer sets currentPath in watchedDirectories

When starting a chain from a watched directory, ensure a SIP's
current path matches the one found in the directory.  This can happen
during AIP reingest, where the last know location is not the watched
directory it is currently in. Do not change currentPath for DIPs, as
they can run in parallel with the originating SIP and overwrite the
SIP's information. Also, some cleanup.
Entry filter in browse is configurable

The filter to determine which files/folders are displayed when browsing the
storage service (ie starting a transfer) is now a parameter, instead of
builtin.  Default is still to display folders but not files.
Stub of add metadata files

wip
Fill in add metadata files

squash with above and add better commit message later
Post API information to storage service

If default setup requested, post the initial user and API key to the
storage service when registering.
Add start reingest endpoint

refs #6488

Add start reingest endpoint to move the new SIP from tmp to the reingest
watched directory.  This is where any pre-processing will happen, such as
clearing remnants of the old SIP from the DB.

Update helpers.json_response to accept a status code to pass to the
response.
Handle failed reingest

refs #6488

Update reject reingest to use normal rejected SIP chain.  Rejected or
failed SIPS attempt to reset their ingest status with the storage service.
Display errors from the storage service properly when starting reingest.