Allow sending binary messages with STOMP

After this change the StompSubProtocolHandler sends STOMP frames
with content-type=octet-stream as a binary WebSocket message.

Issue: SPR-12475
Polish ModelAndViewContainer and update tests
Improve @SessionAttributes support during redirect

Before this change attributes listed with @SessionAttributes would not
be saved in the session when there was a redirect and the controller
method declared a parameter of type RedirectAttributes.

This change ensures it's the "default" model that is always the one
checked for @SessionAttributes under all circumstances since
RedirectAttributes is really only meant to provide String values to
insert into or append to the the redirect URL.

Issue: SPR-12542