feat: added interactivity to CircleLayer & refactored interactivity out into seperate classes

[JaffaKetchup]

Uses same framework as in PolylineLayer/PolygonLayer, but less complex (no pre-projection).

Additionally, to reduce duplication and make it easier to change behaviour in future, all these layers now use a single system, and are only made responsible for hit testing a single element (via an implemented method invoked by the shared hitTest implementation).

• Basic implementation
• Example
• Testing

[josxha]

Could it be that the order of circles is reversed?

The only other thing I'd preferably change is the name of the layer/misc directory since it's now more a layer/common or layer/shared directory.
Other than that it looks good to me. Did some quick testing and all works like intended. Good job👍

[JaffaKetchup]

I believe it is working correctly. Like a Stack, the element at the bottom of the list is rendered on top, and this is reflected in the hit dialog in my testing. (Same as all the other layers, the transparency isn't properly supported by the painter, but this was intentional I believe to improve efficiency.)

I've renamed the directory to 'shared' :)

[josxha]

lgtm, thanks!