- add domains REST api and underlying service
- improved indexing, data flow and search
* Refactors data flow and indexing so that the aggregate data model is
in charge of all data parsing of the user and role model as well as
indexing
* Adds domain data and user identities and further attributes to the
users index and makes them searchable for admins.
* Fixes indexing/facets of email domain values.
* Allows admins to search for restricted email addresses.
* Add admin facets for domain, account status, domain status.
* Add sort options to admin user search.