Add leaf.sh to install a leaf node.  install.sh is modified to just install a
control node.  There is still a lot of code duplication between the two that
can be refactored out.

The long term idea is that install.sh will be just for the control node, and
leaf.sh will be just for the leaf.  If you want an all-in-one, you'd run both.
Adding more suport for leaf node.