[FEATURE SUGGESTION] Outlines around circular point cloud points

[xeolabs]

Add an outline effect for points loaded from LAS/LAZ

[paireks]

I'm curious how to add this, because this one would give me some understanding of a low level part of Xeokit. High level part to change is probably PointMaterial.js by adding either outline width or outline boolean. But I cannot find any continuation. If it's too complex I will skip this one :)