Make singlenode work without redis
XD-506 Support pagination in list() command for jobs.

* Updated code to support the pagination on the existing list command.
* Updated Tests accordingly.
XD-542 Refactor Module to include group and index

Module represents an instance (defined by group and index)
but most APIs passed module, group, and index around.

Encapsulate the group and index and change APIs to just pass
the Module.