Map: added a Google Maps API key setting to settings_2.
Map: the map page has a map now.  Next, to actually fill it with relevant content.
Map: did a bit of configuration with the map appearance, and tried adding a click event to each marker (but haven't tested yet).
Map: there's a marker for every source now (at least every one that has a lat and lon), and an info window pops up when you click a source marker.  Also, below the map, there are sitewide statistics.
Map: public sources now have a link to the source main page, in the marker dialog.