Suggestions on exception handling

[Sam-Kruglov]

1. On any exception caught, there should be a tag error=true set and some log entries like error.*, event, message, stack (see OpenTracing conventions). I also propose to have error.expected=true/false but it's minor.
2. I think point-to-point queries don't have any error handling at all.
3. I think eventHandler.getTargetType().getSimpleName() inside LoggingErrorHandler will include spring proxy like *EnhancerBySpring*.

See my error handlers in TracingAxonConfig. Logging. ErrorLoggingConfig

[smcvb]

From the conventions, I note it's about logging the exceptions, not so much tagging. Regardless, it seems like a regular thing to do with Open Tracing, so thanks for the addition.