consider namespacing all css

[samanpwbb]

Most css rules begin with mapboxgl-ctrl-geocoder in this project, but css is not comprehensively namespaced. There are a few css rules like geocoder-collapsed and geocoder-icon that run the risk of colliding with other names in the global css scope. There are two ways to namespace the css. Either by prefixing all classnames with a shared substring (so .mapboxgl-ctrl-geocoder--geocoder-icon) or by adding specificity (.mapboxgl-ctrl-geocoder .geocoder-icon).