Support for volumetric data when using OpenGL rendering

Nobody has claimed this yet.

## Description of proposed feature

I'm currently working on a project where displaying volumetric data would be a real plus! I'm currently rendering Manim animations using OpenGL and considering that I use the OpenGL-based pyqtgraph package to perform such data visualisation, I'm wondering how hard it would be to implement such a feature in Manim.

## How can the new feature be used?

A VolumeMobject would be implemented in a similar fashion as [pyqtgraph's glvolumeitem](https://pyqtgraph.readthedocs.io/en/latest/api_reference/3dgraphics/glvolumeitem.html).
For those not familiar with pyqtgraph, glvolumeitem allows to render such 3D fields:

## Additional comments

I started looking into reimplementing glvolumeitem using pyglet, but my ignorance of OpenGL is not of a great help. If anyone of you wants to give it a try let me know!

The issue names no repository files, tests, or entry points. Start by reviewing pyqtgraph's glvolumeitem reference and the attempted pyglet reimplementation context, then determine the rendering scope and acceptance criteria for a VolumeMobject supporting volumetric data.

Written by the indexing model from the issue text.