This commit removes the base class WebSocketHandlerAdapterSupport which
was mainly a container for properties. Instead we use a
java.util.Function to create the WebSocketSession which differs in any
way by client and server, which in turn allows HandshakeInfo to become
a simple immutable container once again.
Also for Undertow the WebSocketConnectionCallback implementation has
been moved into the server.upgrade package since it is for server-side
use only.
Issue: SPR-14527
935577f00b