Add putIfAbsent on Cache abstraction

This commit adds a putIfAbsent method to the Cache interface. This
method offers an atomic put if the key is not already associated in
the cache.

Issue: SPR-11400
Improve handling of disconnects in STOMP broker relay

Issue: SPR-11655
Fix @SubscribeMapping MESSAGE response destination

Prior to this commit, @SubscribeMapping mapped methods (backed with
@SendTo* annotations, or not) would send MESSAGEs with the wrong
destination. Instead of using the original SUBSCRIBE destination, it
would use the lookup path computed from the configured prefixes in the
application.

This commit fixes this issue - now @SubscribeMapping MESSAGEs use the
original SUBSCRIBE destination.

Issue: SPR-11648
Expand resource handling mechanism