Add Map Scale

[dloutzenheiser]

There needs to be a scale somewhere on the map.

[theryankelly]

https://docs.mapbox.com/mapbox-gl-js/api/#Scale

[mzagaja]

This is not supported by the React component/library yet so I would need to manually build and link it up. Probably a couple days of work to do this one. Supported controls are listed at https://github.com/uber/react-map-gl/tree/2d9b93293dbc64dccdcf392e9f1bbfd15983ba69/docs/components

[atomtay]

Resolved in commit ac36ba6 with reference to componentDidMount to update map object. I found this ReactMapGL issue response to be particularly helpful in getting the scale to render.