Add possibility to register exception handler to client

[masooh]

At the moment the only possibility to catch an exception (that is caused by for example a timeout or an exception in a ClientRequestFilter) is to wrap the client itself in a try/catch block.

It would be helpful if for an existing client an exception handler could be registered.

This is for instance required if you want to trace the requests and responses. In the Happy Path scenario a trace can be started in ClientRequestFilter and stopped in ClientResponseFilter. In case of an exception the trace cannot be stopped.

An alternative could be an Interceptor. WriterInterceptor cannot be used as it only is called if there is a payload.