Allow auto config

[obvionaoe]

Makes it so that auto is toggleable.

Description

For a manual Proxmox configuration I needed to set an interface which didn't have auto.

Related Issue

#29

Types of changes

• Bug fix (non-breaking change which fixes an issue)
• New feature (non-breaking change which adds functionality)
• Breaking change (fix or feature that would cause existing functionality to change)
• Chore (non-breaking change that does not add functionality or fix an issue)

Checklist:

• I have read the CONTRIBUTING document. - Can't find it
• I have run the pre-merge tests locally and they pass. - Can't find it
• I have updated the documentation accordingly.
• I have added tests to cover my changes. What type of test are required?
• All new and existing tests passed.