Asymetric MarkSymbolizer

[KaiVolland]

Currently the size of a MarkSymbolizer is described by a single value: radius

To allow asymetric symbolizers (eg. rectangle instead of square) the radius property could be replaced with: size which would be typed as [Expression<number>, Expression<number>] or we could add this type to the radius so it would look like this:

radius?: Expression<number> | [Expression<number>, Expression<number>]