Configure spring-xd-ui subproject
    - Added spring-xd-ui as file Resource to REST resourcehandler
     - Added UiResourceIdentifier bean that configures the UI
       based on xd.home
     - This will enable the ui to auto-refresh inside/outside of IDE
    - Added ui as a distribution component inside spring-xd-dirt
     - This will enable spring-xd-ui to be part of xd final dist
    - Deleted unwanted js client libraries