Use d3.js for the gauge

[bvankat]

Replace the Google Chart gauge with a more flexible one, written in D3

Options:

• https://medium.com/d3-datavisualization-examples/gauge-chart-reuable-code-using-d3-js-be706e62f88
• https://hashnode.com/post/d3-gauge-with-needle-in-vuejs-citse28000dd4u553hjfyh9l9
• https://gist.github.com/ameyms/9184728