[Feature]: UPS connections

[gilfreund]

What feature would you like?

Add connections to the UPS. A ups will usually one or more of the following connections

1. RS232 - connected to a hardware (possible a server)
2. USB - connected to a hardware (possible a server)
3. Network - - connected to a network device, and will also have an ip address and a port.

What problem does it solve?

Identify where UPS information is originating from on a network topology

Where would this apply?

Both

Screenshots or mockups (optional)

hardware: 
- kind: Ups
  model: Back-UPS BX2200MI
  va: 2200
  name: APC
  ports:
    - type: usb
    - type: rj45
  network:
    ip: 172.16.10.11
    port: 8880
connections:
- a:
    resource: USW Flex 2.5G 8 PoE
    portGroup: 0
    portIndex: 1
  b:
    resource: Back-UPS BX2200MI
    portGroup: 0
    portIndex: 0