Remove unused npm dependencies

These should have been removed as part of 890cff9.

package.json

@@ -39,17 +39,11 @@
   "homepage": "https://github.com/novnc/noVNC",
   "devDependencies": {
     "@babel/core": "latest",
-    "@babel/plugin-syntax-dynamic-import": "latest",
-    "@babel/plugin-transform-modules-commonjs": "latest",
     "@babel/preset-env": "latest",
-    "@babel/cli": "latest",
     "babel-plugin-import-redirect": "latest",
     "browserify": "latest",
-    "babelify": "latest",
-    "core-js": "latest",
     "chai": "latest",
     "commander": "latest",
-    "es-module-loader": "latest",
     "eslint": "latest",
     "fs-extra": "latest",
     "jsdom": "latest",