Add Cesium shadow functionality to MapStore2

[overkamp]

Description

MapStore2 allows to add 3D models to the 3D map. It supports 3D-Tiles (e.g. buildings or 3D-Mesh).
Example Map with tree models

In Cesium you can configure shadow functionality, e.g.
const shadowMap = viewer.shadowMap;
shadowMap.maximumDistance = 5000.0;
shadowMap.softShadows = true;
viewer.shadows = true;
viewer.terrainShadows = Cesium.ShadowMode.ENABLED

It would be very helpfull to have shadow functionality as in Cesium Viewer.
Application examples in the area of climate impact adaptation are numerous,
e.g. show the effect of tree planting on parking lots.

Acceptance criteria

• the widgets to configure shadows (timeline, animation) are accessible (as plugin?)
• MapStore2 renders shadows as configured

Other useful information