[WIP] Moving OpenStack networks definitions to barclamp-neutron

This is pull request for moving OpenStack Nova networks to barclamp-neutron.
This change will:

- simplify network configuration
- gives better flexibility for user deployments.

Warning!!! Please don't merge this until it will be tested

Depends on:

- crowbar/crowbar#2071
I've added 'conduit' and 'external' attributes