[Java][MicroProfile] Support additionalProperties with Jackson #946

Job	Run time
Build Java Client JDK8 (samples/client/echo_api/java/feign-gson)	51s
Build Java Client JDK8 (samples/client/echo_api/java/apache-httpclient)	1m 10s
Build Java Client JDK8 (samples/client/echo_api/java/okhttp-gson)	1m 0s
Build Java Client JDK8 (samples/client/echo_api/java/resttemplate)	1m 4s
Build Java Client JDK8 (samples/client/echo_api/java/resteasy)	46s
	4m 51s

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