Is your feature request related to a problem? Please describe.
If for example a GeoJSON is used as a layer that has a nested JSON object in the attributes the value should be able to find.

Describe the solution you'd like
If an attribute is defined like this {"name": "detaljplan.beteckning"} and the attribute is a JSON object like below it should be possible to get the attribute value by drilling down in the object.

{
    "detaljplan": {
        "objektidentitet": "0490dfc9-8dxf-4992-bcbb-9ed8ab6137d9",
        "beteckning": "2281K-DP-xx",
        "namn": "xxxx",
        "status": "laga kraft",
        "typ": "detaljplan",
        "datumLagakraft": "1991-12-05",
        "kvalitet": {
            "korrigeradeGranser": true,
            "kontrolleratPlaneringsunderlag": false
        },
        "anvandbarhet": "god"
    }
}

Describe alternatives you've considered
The GeoJSON could be flattened, so all values have a key