Network configuration is extracted into a separate file.
By default this is netconfig.yaml residing near murano.conf
But the name and path can be changed in config file.
Example of net-config can be found in etc/murano/netconfig.yaml.sample
If no file present old behavior is kept
Change-Id: I7b74eea69ee2ffe1c721b751e564b54252dcfbe3
Implements: blueprint configure-environment-network-defaults
0d42f01f68