Fix commandLine initializer

- LauncherApplication's parent Application needs to get
  initialized with CommandLinePropertySourceOverridingInitializer
Fix mqtt default configuration

Split source and sink configuration
XD-1172  Restore --hadoopDistro
Small renaming and comments added
Fix rabbit source

- Fixed rabbit source's connectionFactory to read as "rabbitConnectionFactory"
- Added rabbit.properties under ${xd.config.home}
Fix rabbit source/sink

- Fix config/rabbit.properties to have default values
- Set rabbit sink's 'cloud' profile connection factory to read
  'rabbitConnectionFactory'
Fix typo on property
Added username and password to RabbitSourceOptionsMetadata - WIP

The values aren't applied, needs investigation
XD-1158 Added scripts to exercise jms and mqtt.

Added small pause for test results to return

* For the jms tests the tester sends a http message to an activemq instance at localhost 8161.
So for this test you will need to install activemq.

* For the mqtt tests the XD is still using the mqtt M1 release that has a bug.  The current
workaround is to reference the snapshot instead.
    * So in your build.gradle file replace springIntegrationMQTTVersion = '4.0.0.M1' with springIntegrationMQTTVersion = '4.0.0.BUILD-SNAPSHOT'
    * then run a ./gradlew clean dist
Code updated for based on code review.
Fixed the script to handle changes in contexts.

Properties are not working using defaults at the moment.  This is a workaround.