Remove akanda/nova/virt and clean up neutronv2/api

Removing all akanda/nova/virt code as it is no longer
needed ( the features it provided exist in nova since
havana ). Also removes dhcp_opts cfg option in neutronv2/api since neutron has provided this since icehouse as well.
Removing dhcp_options param docs
Merge pull request #21 from jordant/master

Remove akanda/nova/virt and clean up neutronv2/api