Advanced geometry styles, rule-based labelling, legends etc.

• rule-based symbology and labels

• displaying labels depending on zoom level

example: map of Ireland: show labels between zoom levels 1:5404098 / 1:5100000 and 1:84908

• splitting / converting geometries

cf. https://github.com/MonikaBarget/Europe-and-early-modern-Ireland/issues/14

• creating legends