Moved messaging.support.converter to messaging.converter; moved messaging.support.tcp to messaging.tcp; moved messaging.support.channel to messaging.support itself; moved handler.condition to handler itself; reworked handler.method into handler.support
Renamed handler.support to handler.invocation
Polishing
Create messaging.simp.broker package
Add messaging.simp.user package
Collapse messaging.simp.handler into messaging.simp
Introduced SockJsSession interface and moved SockJsSessionFactory and SockJsServiceConfig to sockjs.transport; added initialize(SockJsServiceConfig) method to TransportHandler interface; extracted TransportHandlingSockJsService from DefaultSockJsService; moved sockjs.support.frame to sockjs.frame and extracted (Default)SockJsFrameFormat from SockJsFrame; moved SockJsHttpRequestHandler to sockjs.support; removed Jackson 1.x support
Fixed detection of generic types and qualifier annotations on scoped-proxy factory methods

Issue: SPR-11116
Polishing