This commit refactors the freebsd networking to:
1. Use predictable network naming
2. Properly handle DHCP vs static networks on up and reload [GH-5852]
3. Perform all networking configuration in a single command to prevent
partial configuration.
https://github.com/mitchellh/vagrant/issues/4307
Fix details:
Pass network interface name to template renderer and use it
in static and dhcp templates to render /etc/rc.conf entries.
modified: plugins/guests/freebsd/cap/configure_networks.rb
modified: templates/guests/freebsd/network_dhcp.erb
modified: templates/guests/freebsd/network_static.erb
Verification scenario:
Check if /etc/rc.conf contains vtnet entries when paravirtualized
NIC devices are used in FreeBSD guest.