refactoring(maplibre): add RasterLayer info, add background switch, add default global layers

UI/Map/MaplibreMap.svelte

@@ -0,0 +1,43 @@
+<script lang="ts">
+  /**
+   * The 'MaplibreMap' maps various event sources onto MapLibre.
+   *
+   * As it replaces the old 'MinimapObj' onto MapLibre and the existing codebase, this is sometimes a bit awkward
+   */
+  import { onMount } from "svelte";
+  import { Map } from "@onsvisual/svelte-maps";
+  import type { Map as MaplibreMap } from "maplibre-gl";
+  import type { Writable } from "svelte/store";
+  import type Loc from "../../Models/Loc";
+  import { UIEventSource } from "../../Logic/UIEventSource";
+
+
+  /**
+   * Beware: this map will _only_ be set by this component
+   * It should thus be treated as a 'store' by external parties
+   */
+  export let map:  Writable<MaplibreMap>
+
+  let center = {};
+
+  onMount(() => {
+    $map.on("load", function() {
+     $map.resize();
+    });
+  });
+  const styleUrl = "https://api.maptiler.com/maps/streets/style.json?key=GvoVAJgu46I5rZapJuAy";
+</script>
+<main>
+  <Map bind:center={center}
+       bind:map={$map}
+       controls="true"
+       id="map" location={{lng: 0, lat: 0, zoom: 0}} maxzoom=24 style={styleUrl} />
+</main>
+
+<style>
+    main {
+        width: 100%;
+        height: 100%;
+        position: relative;
+    }
+</style>