Allow Security Group Empty

### Dependencies

### Feature Request

Hello, I'm trying to use this plugin to create a job where I need to create another cloud in the node. This second cloud has it's own IPs and random mac addresses that idk about so normally through horizon gui I'd just not assign a security group (remove the default) and that would enable other IPs and MACs to go through.

I'm seeing that an entry is currently required in the template with a valid security group to be able to create a node though. Is there a way to allow security group to be empty so one doesn't get assigned to the node?