Add weather radar

[JoshuaCarroll]

The National Weather Service provides a KML feed that can be created at https://idpgis.ncep.noaa.gov/arcgis/rest/services/NWS_Observations/radar_base_reflectivity/MapServer/generateKml. This will produce a KMZ file that contains this:

<NetworkLink>
<name>Weather Radar</name>
<open>1</open>
<LookAt>
<longitude>-91.99314651730941</longitude>
<latitude>43.0148277330171</latitude>
<altitude>0.0</altitude>
<range>1481190.3525374501</range>
</LookAt>
<Link>
<href>https://idpgis.ncep.noaa.gov/arcgis/services/NWS_Observations/radar_base_reflectivity/MapServer/KmlServer?Composite=false&amp;LayerIDs=0%2C3</href>
<viewRefreshMode>onRequest</viewRefreshMode>
<viewFormat>BBOX=[bboxWest],[bboxSouth],[bboxEast],[bboxNorth];CAMERA=[lookatLon],[lookatLat],[lookatRange],[lookatTilt],[lookatHeading];VIEW=[horizFov],[vertFov],[horizPixels],[vertPixels],[terrainEnabled]</viewFormat>
</Link>
</NetworkLink>

We'll need to hide the boundary and label folders to keep the UI clean. So make sure to cache this and store it on the server. Only allow a refresh of the radar image every four minutes at most.