As a user I can define y axis labels

[nhaugo]

The template should be able to define the y axis label. This will be defined as the ylabel in the template.

{
  "id": "ec6c48f4-48ca-4ba7-a842-5b700e19f274",
  "measurement": "system",
  "app": "system",
  "cells": [
    {
      "x": 0,
      "y": 0,
      "w": 4,
      "h": 4,
      "i": "6ec7e632-2c19-475c-8747-56feaacf46ce",
      "range": [0,100],
      "ylabel": "foobar",
      "name": "System Load",
      "queries": [
        {
          "query": "SELECT mean(\"load1\") AS \"load\" FROM \"telegraf\"..\"system\"",
          "db": "telegraf",
          "rp": "",
          "groupbys": [],
          "wheres": []
        }
      ]
    }
  ]
}