Support receiving fragmented STOMP frames

Support receiving STOMP frame split into multiple Websocket
messages, since this is the current behavior of Stomp.js and
Dart STOMP library when frames are bigger than 16 Kbytes.

The new maxFragmentedFrameBufferSize (default 1 Mbytes)
allows to configure the maximum size of the whole fragmented
STOMP frame.

Issue: SPR-11527