[Java Broker] Provide a mechanism by which meta-data can be added to @ManagedAttributeValueType types

Interfaces annotated with

@ManagedAttributeValueType

provide a mechanism by which complex data types can be used to represent properties of configured objects. However there is currently no mechanism by which meta data can be associated with these types (and their attributes) in order that their usage may be described, and that description provided through the auto-generated API docs.

Such a mechanism should be defined, and the auto-generated API docs should display such descriptions