A very early-stage part of addressing #7309. As a result, the Web build (and those dependent on it) will be broken for a while in this PR and its following chain.

The highlights:

1. Drops the namespaced version from the keyman-version build output. Where we're going, we don't need (or want) namespaces.
2. I decided to experiment a bit for DeviceSpec - its related enums are now attached as 'subclasses' of a sort via namespace-aliasing tricks like seen here: https://stackoverflow.com/a/47401896
   • I thought I saw official documentation about this trick at some point, but I'm having difficulty finding that reference at the moment.
3. common/web/utils is now fully ES6-module based; that's what its TypeScript build output produces.
   • https://esbuild.github.io/content-types/#es5 - esbuild doesn't handle transformations to es5 well. Known limitation.
   • tsc, on the other hand, has no such qualms and is happy to transpile to ES5, so we can just bundle that instead.
   • This was the best step I could find to enable the next one.
4. As an early prototype, the utils module build now includes a bundled build version, courtesy of es6build. This relies upon a prior TS build, bundling its JS outputs.
   • As the bundle-build is thus JS-based, it is best to ensure that all import statements refer to .js files, rather than .ts files.
   • If from a separate submodule, use an import on the node-modules version of the path based on the build directory / 'output' version of the submodule.

@keymanapp-test-bot skip