Geographical map: Add GeoJSON layers to map from config

[geppyz]

In the geographical map it would be nice to have a feature to add a custom overlay of geographical data in the form of GeoJSON. This should be configured in the config file and have a feature displayed on the map in combination with OpFab cards that have geographical features.

[geppyz]

Example, in Day and Night mode:

Can be configured in web-ui.json:

 "geomap": {
      "enableMap": true,
      ...
      "layer": {
        "geojson": {
          "url": "http://localhost:8000/liander.geojson",
          "crossOrigin": "anonymous"
        }
      }
    },

GeoJSON data usually has a .geojson or .json file extension but this is not enforced.
Example of the structure:

{
  "type": "FeatureCollection",
  "name": "gelderland",
  "crs": {
    "type": "name",
    "properties": {
      "name": "EPSG:4326"
    }
  },
  "features": [
    {
      "type": "Feature",
      "properties": {
        "identificatie": "PV25",
        "naam": "Gelderland",
        "code": "25",
        "ligtInLandCode": "6030",
        "ligtInLandNaam": "Nederland",
        "fuuid": "provinciegebied.b20f6217-4ee2-41b4-9b4e-0b2a3df9458f"
      },
      "geometry": {
        "type": "Polygon",
        "coordinates": [
          [
            [5.768972,51.752377],
            [5.769299,51.752347],
            [5.769529,51.752326],
            [5.770976,51.752232],
            [5.772424,51.752173],
            [5.772736,51.752162],
            ...
          ]
        ]
      }
    }
  ]
}