Currently the GCETemplateOptions provide a way to specify the URI of a network where the VMs will be attached. The portable TemplateOptions already provides that property as a list of Strings, so the provider-specific options should be removed and the portable one should be used instead:
- If a VM can be attached to multiple networks, then the adapter should honor the property and attach the VM to all them.
- If not, we should validate the options and fail giving a proper feedback to the user.
- If no network is explicitly provided, the VMs will be attached to the default network, as suggested in https://github.com/jclouds/jclouds-labs-google/pull/138