Creating Custom Networks

**Describe the issue**
If the UTM is really plays to be a serious vm solution it will require to have a feature to make backups and set custom netowrks like vmware.

Are there any solutions to this? If there is not I will open a feature request about it.

The issue names no files, tests, or entry points; begin by locating UTM’s existing network configuration and backup-related code. Done would require an agreed design and an implemented custom-network feature, but the issue does not define the network options or acceptance criteria.

Written by the indexing model from the issue text.