feat(maps_utils): improved marker + marker shadow, fix scrolling on mobile devices

maps_utils/static/maps_utils/geo-feature-collection.css

maps_utils/static/maps_utils/geo-feature-collection.js

maps_utils/static/marker-numbered.svg

maps_utils/static/marker.svg

maps_utils/templates/maps_utils/marker-numbered.svg.template

maps_utils/templates/maps_utils/marker-shadow.svg

maps_utils/templates/maps_utils/marker.svg.template

maps_utils/urls.py

maps_utils/views.py