Unable to initialize REST resources in tests

[valdar]

Tests logs contains:

org.apache.kafka.connect.errors.ConnectException: Unable to initialize REST resources
	at org.apache.kafka.connect.runtime.rest.RestServer.initializeResources(RestServer.java:301) ~[connect-runtime-2.4.1.jar:?]
	at org.apache.kafka.connect.runtime.Connect.start(Connect.java:54) ~[connect-runtime-2.4.1.jar:?]
	at org.apache.camel.kafkaconnector.services.kafkaconnect.KafkaConnectRunner.run(KafkaConnectRunner.java:198) ~[test-classes/:?]
	at org.apache.camel.kafkaconnector.services.kafkaconnect.KafkaConnectRunnerService.lambda$start$0(KafkaConnectRunnerService.java:107) ~[test-classes/:?]
	at java.util.concurrent.FutureTask.run(FutureTask.java:266) [?:1.8.0_242]
	at java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1149) [?:1.8.0_242]
	at java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:624) [?:1.8.0_242]
	at java.lang.Thread.run(Thread.java:748) [?:1.8.0_242]
Caused by: java.lang.NullPointerException
	at org.eclipse.jetty.server.handler.ContextHandler.doStart(ContextHandler.java:802) ~[jetty-server-9.4.20.v20190813.jar:9.4.20.v20190813]
	at org.eclipse.jetty.servlet.ServletContextHandler.doStart(ServletContextHandler.java:276) ~[jetty-servlet-9.4.20.v20190813.jar:9.4.20.v20190813]
	at org.eclipse.jetty.util.component.AbstractLifeCycle.start(AbstractLifeCycle.java:72) ~[jetty-util-9.4.20.v20190813.jar:9.4.20.v20190813]
	at org.apache.kafka.connect.runtime.rest.RestServer.initializeResources(RestServer.java:299) ~[connect-runtime-2.4.1.jar:?]```
This is most probably due to how kafka connect environment is initialized mimiking what kafka connect standalone dose and missing the REST server init part.

[valdar]

Talking to @orpiske this is somehow related to #118 in the sense that using closer to real embedded Kafka connect embedded environment might solve both. An enhancement was already logged to do so in #105

The idea is to see if using org.apache.kafka.connect.util.clusters.EmbeddedConnectCluster solves both issues and then evaluate from there how to integrate it in the broader integration test facilities that we have in place.

[valdar]

fixed with #138