AMBARI-6125. changes:
new:
             addHost - adds a registered host to the cluster
             removeHost - gracefully decommission and remove the host from the cluster (synchronous)
             waitForRequestsToFinish - waits for any given request to finish, used to synchronize rest calls
             decommissionDataNode - decommissions the datanode on a given host
             decommissionNodeManager - decommissions the nodemanager on a given host
             decommission - can decommission any given components which supports decommission
             deleteHostComponents - deletes the given components from a host
             deleteHost - deletes the host from the cluster
             installComponentsToHost - can install components from either blueprint or from the specified component list
             restartServiceComponents - restarts the given services components on all hosts
             startComponentsOnHost - starts the provided components on a host
             stopComponentsOnHost -  stops the provided components on a host
             validateBlueprint - can validate the blueprint for recommendAssignments
             modifyConfiguration - can modify any services configuration (the whole config must be provided)
             getHostNamesByState - retrieves the hosts by state
             getPublicHostNames - returns the public host names which the provided host components are installed to
             getInternalHostNames - returns the internal host names which the provided host components are installed to
             getClusterHosts - returns only the hosts which are part of the cluster
             resolveInternalHostName - can resolve a host's internal name to the public one

             modified:
             recommendAssignments - host group and host recommendation changed:
               - at least host group number of host is required
               - if there are more hosts than host groups in the blueprint
                 all host group get a single node and the leftover hosts are distributed
                 among all the slave_X host groups
             getInstallProgress - renamed to getRequestProgress
             startAllServices - return type changed
             stopAllServices - return type changed

             blueprints:
             HDP single/multi node blueprints added to defaults

             dependencies:
             commons-io added