Fix map gravity bugs

[CamoRF]

• Shipment: shipping containers/trailers float when bottom ones are destroyed.
• Expansion: re-enable destruction for bridge on when gravity issue with crates is fixed
• Frost: cranes with constraints have glitched physics, cloned smokestack with child floats in air when bottom part is destroyed.
• Factory, cloned smokestacks on hill?
• Shipment: shipping containers/trailers float when bottom ones are destroyed.
• Partial Recall: smokestacks with children float when destroyed
• Junkyard: some shipping containers/trailers float when bottom ones are destroyed.

Requires Nanoforge fixes with issue possibly related to world_anchors.