Builds a service Object Map containing a partial set of objects within the given target path,
where the map's key for each object is the relative path to the object.
If the method is asked to perform a complete listing, it will use the
#listObjectsThreaded(StorageService,String,String) method to list the objects
in the bucket, potentially taking advantage of any bucket name partitioning
settings you have applied.
If the method is asked to perform only a partial listing, no bucket name
partitioning will be applied.