Figure out way to differentiate vehciles automatically

[seanauff]

The current method of defining which vehicle is in use is manual and relies on user entered data. An automatic way is preferred. A possibility is the use of the VIN, where the VIN would be sent with each Torque message and stored as a InfluxDB tag. Torque does not have a native PID for VIN, but VIN does exist as a readable field by OBD2. Torque also has a "custom PID" option, but I have not been able to get it to return the VIN. More info here: https://en.wikipedia.org/wiki/OBD-II_PIDs#Service_09