Improve geoserver config to better calculate bounding boxes * Disable the use of estimated extents for the postgis storage configuration for geoserver, which is set via the gemma middleware. This way we are able to get better bounding boxes for many layers where the postgis function `ST_EstimatedExtent()` would be far off.

teichmann@intevation.de = sascha.teichmann@intevation.de
bernhard.reiter@intevation.de = bernhard@intevation.de