Change to better bundler

[konhi]

I suggest changing the default bundler from webpack to something different, such as esbuild or swc. I moved to esbuild, and instantly noticed

• surprising build times while developing with wrangler dev 🥰
• support for Module Workers (webpack doesn't seem to support for export, correct me if I'm wrong) - Cloudflare advises to use it, as it gives few advantages including support for Durable Objects

Example template is shown there: https://github.com/codewithkristian/esbuild-typescript-modules-workers-template

[JacobMGEvans]

This example is now using Wrangler2 and has it as a dependency which utilizes ESBuild currently.