Fix endlessly problematic filtering behaviour (again)
Overhaul the event system. DAOs must now have an implicit RestEventHandler
in scope through which to signal events (currently only create, update,
delete). This is passed on through the controller global config and
exposed in the ControllerHelpers trait. This change makes testing indexing
and potentially other event-hook actions much easier. The remnants of the
old Solr indexing stuff have been removed in addition.
Clean up global config by injecting search dispatcher separately.