Fix approve transfer API

refs #6583

MicroServiceChainChoice had been updated to have a foreign key to
MicroServiceChain which can be used directly, instead of fetching the
MicroServiceChain with the correct UUID.  Update approve_transfer for
this change.
Cleanup

Add instruction to API whitelist template, updated code to match.
Whitelisted IPs are now whitespace separated, instead of newline
separated.  Add display functions for MicroServiceChain and
MicroServiceChainChoice.  Cleanup imports.
Update dev-helper to delete pyc, backlog, storage

refs #6247

Update dev-helper to delete pyc's and pyo's when the DB is recreated.
Add new option to clear the transfer backlog and default AIP storage
location.
Fix METS namespaces

refs #6676

Fix the AIP METS to only declare the namespaces it's actually using,
notably XSI, xlink, and METS as the default. Replace all 'from
archivematicaXMLNamesSpace import *' with explicit imports and update
references.
Merge branch 'dev/issue-6676-mets' into dev/issue-6567-combined