Create a Django admin action to allow retrieval of
the expected domain configuration from dimail.
These values shouldn't change unless external
intervention occurs. An admin command seems sufficient to handle
hypothetical changes.
Adapt fetch domain status call to manage internal and external
fixes required. Use the new status 'action required' to
manage actions expected from support.
Call a new dimail endpoint to run a fix for internal checks
when all external checks are OK.
