* fixes bug where holes in stored geometries would not be rendered properly on initial loading the map client
* drawback: multiple polygons are treated as a single feature on the map client. Not a real issue but maybe we can find a better solution to this
* quality of life: renders geometry area in m² on detail and report view
* enhances visualization of editable column on tables
* simplifies code
* enhances visualization of parcel_group column on tables
* WIP: Ordering on intervention table is odd. Same results are being displayed on page 2. Needs further analysis and fixing!
* disables ordering of parcel_group ("Gemarkung") column on tables
* ordering can not be done properly due to more complex nature of this column's content
* introduces "Keine Geometrie vorhanden" message instead of hour glass icon on entries where no geometry has been entered yet
* properly orders last_modified column by moving null values to the lower end of the ordering
