Implement a 3D sphere mode for the Markers module

[moxvallix]

Type of change

• [ ] Bug fix
• [x] New feature

Description

Adds a 3D sphere as a possible marker.

Such a feature is useful for visualizing the spawn radius of various farms. Also looks cool.

Most of the code already existed in Sphere2DMarker, just modified it to render all layers at once, and optimized it a bit, as it has to do a lot more work to render the full sphere.

Slider caps the radius at 64 (making a diameter of 128, which is useful for most farms), but users can use the text input to make it larger if they really need to. Anything larger than 64 might cause frame drops (512 ran at 7fps for me).

How Has This Been Tested?

Checklist:

• [x] My code follows the style guidelines of this project.
• [ ] I have added comments to my code in more complex areas.
• [ ] I have tested the code in both development and production environments.