Add senlin-dashboard in doc/source/overview.rst
Add senlin-dashboard in doc/source/overview.rst

Change-Id: Ide9fd1d24d7ac45ef85a411ac61b58b28576c907

stackforge/senlin,openstack/senlin,tengqm/senlin-container,tengqm/senlin-container,openstack/senlin,stackforge/senlin,openstack/senlin