chg:user: Allow specifying edge properties (color/width)
Chg: User: only validate IP on Layer 3 devices for VIRL-672
Chg: User: add "external_connector" device_type for VIRL-672
Chg: User: support custom unsupported server templates for VIRL-378
Chg: User: Handle IP addresses on L3 devices for VIRL-372