Add exception handling of asynchronous method

Prior to this commit, an exception thrown by an @Async void method
was not further processed as there is no way to transmit that
exception to the caller.

The AsyncUncaughtExceptionHandler is a new strategy interface that
can be implemented to handle unexpected exception thrown during the
invocation of such asynchronous method.

The handler can be specified using either the XML namespace or by
implementing the AsyncConfigurer interface with the EnableAsync
annotation.

Issue: SPR-8995