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.

The gemma database schema requires PostgreSQL >= 11.

`dot.tmpl` is a template file for `postgresql_autodoc`
to be more similiar to UML and leave out some less useful labels.

See  `../docker/README.md`