Use vite to build

[flackr]

This is an experiment to see how vite works for #219. This PR right now only contains minimal changes to switch to vite. This fixes #188 as the build forces "use strict".

[flackr]

This is looking pretty promising so far.

Going back to the list of goals, we should be able to:

1. Create multiple build targets. We can either use environment variables, or different vite config files to control this.
2. Reserved names can be specified by setting build.terserOptions to include a reserved list of names to not mangle.
3. Typescript support is as easy as invoking tsc before vite build.
4. I don't think auto-publishing to npm would be part of the build system. I think this would be better suited as a github action.
5. The github build action for vite seems to be 1s to microbundle's 4s. Vite also has a magically auto-updating dev server which reloads browser windows for extra speed.
6. As with 4, I think this is best met with github actions?

[flackr]

@bramus @johannesodland I think we should go ahead with this, and then I can make followon PR's to meet the specific goals as outlined in #224 (comment)