Improve Map Component

[kamicut]

The map component is now written in an imperative style instead of a declarative style, using map.addLayer instead of react components. This was done for the following reasons:

• We tried using the beforeId layer ordering mechanism in maplibre, but adding a TMS layer after map load would be push it to the top of the layer stack.
• If the user asks for a location (“I want alerts for Berlin”) followed by another location request (“actually I want alerts for Munich”) we have to dynamically replace the geojson sources in the existing location layer.

For these reasons it was easier to use an imperative style and useEffect. However this decreased the readability in the component and made it more complicated. This ticket tracks how to reduce this complexity.