Configure Babel for JavaScript and TypeScript

Fix #3714
- script/fetch-examples calls script/examples
- inside script/examples we import the newly migrated /server/models/user file
- this file needs to know to try to resolve both ts and js files, instead of just js

Author: clairep94

server/scripts/fetch-examples.js

@@ -1,4 +1,7 @@
-require('@babel/register');
+require('@babel/register')({
+  extensions: ['.js', '.ts'],
+  presets: ['@babel/preset-env', '@babel/preset-typescript']
+});
 require('regenerator-runtime/runtime');
 const dotenv = require('dotenv');