Add udevadm script to allow serial port enumeration to work under OpenWRT (#900)
Add udevadm script to allow serial port enumeration to work under OpenWRT (#900)

* Add udevadm script to allow serial port enumeration to work under OpenWRT

To test, I ran using list-ports.js from the serial-adapter.
```
./list-ports.js
```
will use the udevadm builtin to your dev machine.
```
PATH=PATH-TO-GATEWAY/tools:${PATH} ./list-ports.js
```
will use this udevadm.

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