Code review comment for lp:~allenap/maas/fix-makefile-write-dhcp-stuff

If these scripts are only needed by packaging then we can just use the
python -m ... forms. For users, it may be worth having a single
front-end script, e.g. maas-provision or maas-worker, that follows the
verb pattern, or subparsers as argparse calls it. In other words,
something like:

  maas-provision verb --verb-specific-option

Or, more specifically:

  maas-provision dhcp-config --subnet ...