The dataset default style shouldn't be editable from a map

[giohappy]

We have integrated the native MapStore's TOCSettings, and the related style editor, inside the client, replacing the previous custo style editor and its custom logic.

Now we have a problem: the style editor doesn't prevent editing the default style for a dataset. If a user inadvertently modify the style of a layer without creating a new one for the specific map, it modifies the style associated with the dataset, affecting all maps (and the dataset preview) where the the dataset is used.

A solutions, proposed by @allyoucanmap, is implementing a configuration for the MS StyleEditor to prevent editing the default style of a datset, which is an information available to MapStore, since it's reported by Geoserver.

It could be named cfg.enableEditDefaultStyle

[dsuren1]

Reference issue: geosolutions-it/MapStore2#10902