WireFrustum: javadoc + add makeGeometry(Camera) method

[capdevon]

These changes focus on improving the readability, robustness, and maintainability of the WireFrustum class.

1. Comprehensive Javadoc Documentation
   Extensive Javadoc comments were added to the class, constructors, and all methods. This significantly enhances code understanding and future maintainability.

2. Robust Input Validation
   Implemented explicit checks in the WireFrustum constructor and the update method to ensure that the points array is never null and always contains exactly 8 Vector3f objects. This prevents common runtime errors such as NullPointerException and IndexOutOfBoundsException, making the class more reliable.

3. Minor Code Refinements
   Small adjustments were made to the update method to explicitly clear the existing FloatBuffer before writing new data, enhancing clarity in buffer handling.

New Utility Method: makeGeometry(Camera camera) for Debugging.
A dedicated static method, makeGeometry, was added. This method specifically generates a Geometry object representing the wireframe viewing frustum of any given camera. This is an invaluable tool for debugging and visualizing the camera's exact viewing volume within the 3D scene, which helps in understanding culling, shadow calculations, and general scene setup.

[yaRnMcDonuts]

Looks good to me, I'll merge this PR (as well as a few other of your PRs from last week that I've also already marked approved) in the next day or 2.