Expand ReactorQueryGateway interface

[smcvb]

A lot of methods are already provided through the ReactorQueryGateway, expanding on the regular QueryGateway. The only thing which is currently really missing, is the option to only provide the queryName when issuing a query.
Currently the ReactorQueryGateway expects the usage of a Query Payload object to be able to dispatch a query.

[smcvb]

Removing the milestone in favor of making a 4.6.0 release soon. This issue will be reevaluated once we start the new planning phase.

[smcvb]

Lowered the priority, as the insights into AF5 show we might drop the queryName field entirely in favor of a QualifiedName field. Whether that suffices as the replacement for this method, if it'll survive at all, is the question that remains to be answered at a later stage.