This task captures the discussion we have had in the epic about implementing the possibility to implement the concept of Layer Filter.

A Layer Filter acts directly on a layer coming from GeoServer and filter its content upfront. Once a filter is created for a layer:

• the map content for this layer is automatically filtered
• if we issue a GetFeatureInfo, the features we get are automatically filtered using this filter
• if we open the FeatureGrid for this layer, the features we get are automatically filtered using this filter. Any additional filter we define using the Query Builder or the Quick Filters will go in AND with the layer filter.
• if we create a Widget from this layer, the features we get are automatically filtered using this filter. Any additional filter we define using the Query Builder or the Quick Filters will go in AND with the layer filter.
• the filter will be persisted along with the other layer options, inside the map object on map save. If we reload the map once it's saved the filter will be reapplied.

A filter icon shall be shown in the TOC right next to the layer title to notify that the layer is filtered. The Filter Icon should be toggable to temporarily disable the filter from anywhere above.