Convert build scripts from CommonJS to ES Modules (#416)

* Convert build scripts from CommonJS to ES Modules

- Convert all eng/*.js files to ES Modules (.mjs)
- Update package.json scripts to reference .mjs files
- Fix ERR_REQUIRE_ESM error with vfile v6.0.3
- Add __dirname polyfills for ES Modules

* completing the migration of all files to es modules

---------

Co-authored-by: Lyubomir Filipov <lyubomir.filipov@jakala.com>
Co-authored-by: Aaron Powell <me@aaron-powell.com>

package.json

@@ -6,11 +6,12 @@
   "private": true,
   "scripts": {
     "start": "npm run build",
-    "build": "node ./eng/update-readme.js",
+    "build": "node ./eng/update-readme.mjs",
     "contributors:add": "all-contributors add",
     "contributors:generate": "all-contributors generate",
     "contributors:check": "all-contributors check",
-    "validate:collections": "node ./eng/validate-collections.js"
+    "collection:validate": "node ./eng/validate-collections.mjs",
+    "collection:create": "node ./eng/create-collection.mjs"
   },
   "repository": {
     "type": "git",