Rolling upgrade connect source

In order to make the cluster migration as automatic as possible we need a way to temporarily add a remote store to a cache for the duration of the migration.

This would mean adding the following method to RollingUpgradeManager:

public void connectSource(@Parameter(name="migratorName", description="Specifies the name of the migrator to use. Set hotrod as the value unless using custom migrators.") String migratorName, @Parameter(name="uri", description="The URI pointing to the source.") throws Exception;

disconnectSource should be modified to be able to remove a store added above instead of the current disabling.

The CLI should then be extended to add a migrate cluster connect command