chore: migrate from CJS to ESM

[szymonrybczak]

Summary

Migrates to ESM.

Test plan

pnpm build should produce build in ESM format.

[mdjastrzebski]

I've noticed some issues with the current state of the branch:

1. d.ts files are generated per source file, while index.js seems to be bundled together. These should probably be the same, either per-file or bundled.
2. There is no bin.js in create-app
3. test-helpers is having dist in top-level folder, while create-app has it's own in packags/create-app. I think the second option is better if we want to run binaries, as we don't have to install deps in dist then.

[mdjastrzebski]

4. __dirname does not seem to get resolved properly during build:

[mdjastrzebski]

I've done a round of checks and following things now work:

• pnpm build and test are working fine
• There is a bundled bin.js in packages/create-app/dist and it runs correctly

One piece that could be fixed is that while JS get's bundled, the d.ts are still geneated on a per-file basis:

The test-helpers packaged does not get build automatically (even with pn build = nx run-many -t build). But if you build it with nx build test-helpers then it is build in top-level dist/packages/test-helpers and JS are also generated on per-file basis (unlike create-app) 🤔

[szymonrybczak]

@mdjastrzebski after migration to tsc all things that you've mentioned should be resolved 👍