Fix layering, custom Three.js objects render _behind_ certain map features

[trusktr]

Describe the bug

Three.js objects inserted into the scene may render behind map features, whereas the map features should render behind the objects, and therefore can sometimes not be visible.

To Reproduce

1. place a Three.js object near the ground somewhere.
2. Observe that map features cover the object

Expected behavior

Objects that are physically in front of map features should render in front.

Screenshots

TODO

Desktop (please complete the following information):

Any OS.

Smartphone (please complete the following information):

Any device.

Additional context