Update leaflet markers based on feature type and unknown magnitude

Each feature has properties.type, and that type will either be 'earthquake' or some other non-earthquake value such as: quarry blast, explosion, sonic boom, etc. If the feature type is 'earthquake', then we will use the currently prescribed marker styles. The other styles will be as follows:

• Unknown magnitude, same color (based on age), dotted circle, https://github.com/usgs/earthquake-latest-earthquakes/blob/4ca3187edd2d3c515164c9dee386a1e5e55f2088/src/htdocs/css/map/_EarthquakeLayer.scss#L34
• non-earthquake, same color (based on age) and same size (based on magnitude) as earthquake markers, but a diamond shape (rotate a square marker 45deg).