Refactor GridHelper to support different size and divisions

[Makio64]

Description

GridHelper can now receive a width/height and different division. The previous signature still work ( synthax inspired by animejs )

new GridHelper( size , divisions, color1 , color2 )
new GridHelper( 10 , 10, 0xff0000 , 0x00ff00 ) create a grid of 10x10 divide 10 times.
new GridHelper( [5,10] , [5,2], 0xff0000 , 0x00ff00 ) create a grid of 5x10 divide 5 time on x axis and 2 times on z axis

Can also mix the int / array for size/divisions

[github-actions]

📦 Bundle size

Full ESM build, minified and gzipped.

	Before	After	Diff
WebGL	689.92 170.93	690.05 170.98	+133 B +46 B
WebGPU	813.52 219.09	813.65 219.13	+133 B +40 B
WebGPU Nodes	813.03 218.94	813.16 218.98	+133 B +44 B

🌳 Bundle size after tree-shaking

Minimal build including a renderer, camera, empty scene, and dependencies.

	Before	After	Diff
WebGL	462.94 111.81	462.94 111.81	+0 B +0 B
WebGPU	537.35 145	537.35 145	+0 B +0 B
WebGPU Nodes	493.46 134.72	493.46 134.72	+0 B +0 B

[Mugen87]

I'm not sure about this, tbh. It seems having grids like that is a quite specific thing. In order to keep the helper straightforward, I currently tend to leave this bit out.

[Makio64]

@Mugen87 I often found myself needing it while doing editor or prototyping so I though it might be profitable to others.

Here some use cases not squared :

• "Infinite runner" level editor : long tiles of 3 x 100 to put obstacles on it
• Rooms editor prototype : placing items on a grid based on a wall / floor in a not cubic room
• Dungeon game prototype : the fight in each rooms are on a grid based but the battlefield is not always squared

But I think the code added is too big for the usage, I will try to make it more small and elegant

[Makio64]

@Mugen87 i reduced the code, its 67lines in total but if you think its too much, maybe in addons or in a Gist

[Mugen87]

The new approach is indeed cleaner. Let's see what @mrdoob thinks about this feature.