chore: remove closure vars in favor of static fields

[abernier]

when subclassing, due to :

camera-controls/src/CameraControls.ts

Lines 36 to 62 in 1ca71a0

	const VERSION = '__VERSION'; // will be replaced with `version` in package.json during the build process.
	const TOUCH_DOLLY_FACTOR = 1 / 8;
	const isMac = /Mac/.test( globalThis?.navigator?.platform );
	let THREE: THREESubset;
	let _ORIGIN: _THREE.Vector3;
	let _AXIS_Y: _THREE.Vector3;
	let _AXIS_Z: _THREE.Vector3;
	let _v2: _THREE.Vector2;
	let _v3A: _THREE.Vector3;
	let _v3B: _THREE.Vector3;
	let _v3C: _THREE.Vector3;
	let _cameraDirection: _THREE.Vector3;
	let _xColumn: _THREE.Vector3;
	let _yColumn: _THREE.Vector3;
	let _zColumn: _THREE.Vector3;
	let _deltaTarget: _THREE.Vector3;
	let _deltaOffset: _THREE.Vector3;
	let _sphericalA: _THREE.Spherical;
	let _sphericalB: _THREE.Spherical;
	let _box3A: _THREE.Box3;
	let _box3B: _THREE.Box3;
	let _sphere: _THREE.Sphere;
	let _quaternionA: _THREE.Quaternion;
	let _quaternionB: _THREE.Quaternion;
	let _rotationMatrix: _THREE.Matrix4;
	let _raycaster: _THREE.Raycaster;

it becomes difficult to override any method that uses thoses module closured vars

import * as _THREE from "three";

const _box3A = new _THREE.Box3(); // ⚠️ we should redeclare any closure-var

class MyCameraControls extends CameraControls {
  fitToBox() {
    // ...
    const aabb = (box3OrObject as _THREE.Box3).isBox3
      ? _box3A.copy(box3OrObject as _THREE.Box3)
      : _box3A.setFromObject(box3OrObject as _THREE.Object3D);
    // ...
  }
}

with this PR, all closure vars are now consumed as eg: this. so more portable

[abernier]

in bb73162

i'm exporting more so, when subclassing, we can easily reuse without re-declaring utilities like approxEquals or anything