Create a collision mask for editing FeatureLayers

[MathiasBaumgartinger]

As of now it would technically be possible to place a windturbine onto another windturbine. We argued that using a collision mask for the speciifc tasks of a layer.

Most trivially, we could distinguish between a Terrain-mask and an Object-mask, depending on the current action one wants to take (e.g. Moving an object, the Object-mask bit would be set so you can collide with a specific object. For adding a new object the Terrain-mask bit would be set).

This does not cover all "missuses" (e.g. what happens when I go into edit mode in the Windmill-layer and edit the collision with a PV-asset), but for now this should be more than sufficient.