Feature: Placement of prefabs from their bounds/mesh centre

[WooshiiDev]

Feature Description
Place prefabs based on the centre point of their mesh or bounds.

Reason for feature
This will allow for easier and more accurate placements of prefabs without the need to adjust after. If the prefab origin is offset from the centre, inaccuracies may occur when this is not desired.

Secondly, #1 (Prefab Tiling) will require some of the logic from this feature to correctly function, this provides more reason to implement this.