maps miscellany

requires new localsettings:

MAPS_LAYERS = {
    'Maps': {
        'family': 'mapbox',
        'args': {
            'apikey': 'dimagi.map-0cera12g'
        },
        'default': True,
    },
    'Satellite': {
        'family': 'mapbox',
        'args': {
            'apikey': 'dimagi.map-jvzwkbwu'
        },
    },
}