Relocate the Configuration from `.gpkg` to a LandscapeLab specific format `.ll`

[MathiasBaumgartinger]

After careful consideration, we came to the conclusion that the configuration inside the geopackage is a limitation and frustrating to work with. Furthermore, it feels inconsistent when loading geolayers from multiple gpkgs and only one has the configuration in it. This will also ease the further development (e.g. saving a configuration).

The file will be ended with .ll and represent a json format. An exemplary terrain configuration could look like the following:

{
    LayerCompositions: {
        Terrain: {
            type: "RealisticTerrain",
            height: "path/to/gpgk:layer_name",
            ortho: "path/to/gpgk:layer_name""
        }
    }
}

[kb173]

Full basic config for a GeoPackage:

{
    "LayerCompositions": {
        "Terrain": {
            "type": "RealisticTerrain",
            "dhm": "./LL_Wolkersdorf.gpkg:dhm",
            "ortho": "./LL_Wolkersdorf.gpkg:ortho",
            "ndom": "./LL_Wolkersdorf.gpkg:ndom",
            "landuse": "./LL_Wolkersdorf.gpkg:landuse"
        },
        "Buildings": {
            "type": "Buildings",
            "polygons": "./LL_Wolkersdorf.gpkg:buildings",
            "dhm": "./LL_Wolkersdorf.gpkg:dhm",
            "height_attribute_name": "ndom_mean",
            "height_stdev_attribute_name": "ndom_stdev",
            "slope_attribute_name": "slope_mean",
            "red_attribute_name": "r_median",
            "green_attribute_name": "g_median",
            "blue_attribute_name": "b_median"
        },
        "Vegetation": {
            "type": "Vegetation",
            "dhm": "./LL_Wolkersdorf.gpkg:dhm",
            "landuse": "./LL_Wolkersdorf.gpkg:landuse"
        },
        "Power Lines": {
            "type": "ConnectedObject",
            "dhm": "./LL_Wolkersdorf.gpkg:dhm",
            "lines": "./LL_Wolkersdorf.gpkg:power_lines",
            "selector_attribute_name": "power",
            "fallback_connector": "res://Objects/Power/LowVoltagePowerPole.tscn",
            "fallback_connection": "res://Objects/Connection/MetalSteelCableSmall.tscn",
            "connectors": {
                "minor_line": "res://Objects/Power/LowVoltagePowerPole.tscn",
                "line": "res://Objects/Power/HighVoltagePowerLine.tscn"
            },
            "connections": {
                "minor_line": "res://Objects/Connection/MetalSteelCableSmall.tscn",
                "line": "res://Objects/Connection/MetalSteelCableBig.tscn"
            }
        }
    },
    "Scenarios": {
        "Basic": {
            "layers": [
                "Terrain",
                "Buildings",
                "Vegetation",
                "Power Lines"
            ]
        }
    }
}

[kb173]

Will be adapted like this for better readability and easier automated loading:

...
        "Terrain": {
            "type": "REALISTIC_TERRAIN",
            "layers": {
                "height_layer": "./LL_joglland.gpkg:dhm",
                "texture_layer": "./LL_joglland.gpkg:ortho",
                "surface_height_layer": "./LL_joglland.gpkg:ndom",
                "landuse_layer": "./LL_joglland.gpkg:landuse"
            }
        },
        "Buildings": {
            "type": "POLYGON",
            "layers": {
                "polygons": "./LL_joglland.gpkg:buildings",
                "dhm": "./LL_joglland.gpkg:dhm"
            },
            "attributes": {
                "height_attribute_name": "ndom_mean",
                "height_stdev_attribute_name": "ndom_stdev",
                "slope_attribute_name": "slope_mean",
                "red_attribute_name": "r_median",
                "green_attribute_name": "g_median",
                "blue_attribute_name": "b_median"
            }
        },
...