Do it on the prepack step, so it gets built before we upload the build
artifact.

Include a type comparison utility to compare auto-generated vs hand-crafted
types.

Thanks @sapkra for working on these! ❤️

This is just the stepping stone towards the goal of eventually having
lib-jitsi-meet fully written in JS.

- introduce ts-loader for webpack
- webpack will continue generating the UMD bundle
- tsc will generate an ES6 module
- output all bundles to dist/

Build as follows to build (production) bundle size stats:

npx webpack -p --progress --analyze-bundle

Then open the report:

npx webpack-bundle-analyzer stats.json

In order to include browser capabilities in RTCBrowserType I needed to
refactor RTCBrowserType.