Consider moving from Webapck to esbuild for build tool

**Is your feature request related to a problem? Please describe.**

Webpack build times are slow and config is complex.

**Describe the solution you'd like**

Consider moving to [esbuild](https://github.com/evanw/esbuild) to dramatically speed up build times and also unlock usage of tools like [Vite](https://vitejs.dev/) and [Snowpack](https://www.snowpack.dev/) in the development toolchain which make the developer experience much nicer.

**Describe alternatives you've considered**

The following are also alternatives to esbuild that aim to significantly improve bundle build times:

- [swc](https://swc.rs/)
- [packem](https://packem.github.io/)

**Additional context**

I realise this may be quite a significant refactor as dependencies are likely to need updating which may introduce breaking changes. As such, this could become a long term goal if the community thinks it's worth the effort.