Move worker into webpack build

The jscad worker code was hosted as a static asset, making it odd
javascript where we have to be conscious of what javascript features we
can use and if it will work on older browsers, plus it can't be
typescript like the rest of the codebase.

Since redwood 0.36 we using webpack 5 should make loading workers easy
https://webpack.js.org/guides/web-workers/
But I had trouble with this (see:
https://community.redwoodjs.com/t/has-anyone-tried-workers-with-webpack-5-rw0-36-x/2394)
and instead used the webpack 4 loader without any issues

This issue relates to #411 , and is a checklist item on #444
Resolves #494

app/web/src/helpers/cadPackages/jsCad/jsCadController.tsx

@@ -16,6 +16,7 @@ import {
   Mesh,
 } from 'three'
 import { jsCadToCadhubParams } from './jscadParams'
+import TheWorker from 'worker-loader!./jscadWorker'
 
 const materials = {
   mesh: {
@@ -134,19 +135,7 @@ export const render: DefaultKernelExport['render'] = async ({
 }: RenderArgs) => {
   if (!scriptWorker) {
     const baseURI = document.baseURI.toString()
-    const scriptUrl = '/demo-worker.js'
-    const script = `let baseURI = '${baseURI}'
-    importScripts(new URL('${scriptUrl}',baseURI))
-    let worker = jscadWorker({
-      baseURI: baseURI,
-      scope:'worker',
-      convertToSolids: 'buffers',
-      callback:(params)=>self.postMessage(params),
-    })
-    self.addEventListener('message', (e)=>worker.postMessage(e.data))
-    `
-    const blob = new Blob([script], { type: 'text/javascript' })
-    scriptWorker = new Worker(window.URL.createObjectURL(blob))
+    scriptWorker = new TheWorker()
     let parameterDefinitions = []
     scriptWorker.addEventListener('message', ({ data }) => {
       if (data.action == 'parameterDefinitions') {