It turns out this command is not installed by default on macOS.
Fortunately the code doesn’t really require it to be used.

This PR converts everything (aside from electron) from CommonJS to ESM.
It is needed to reduce the changes that will happen during the migration
to Typescript (as TS does not play nice with CJS).

Basically:
- rewrite `require()` to `import`
- rewrite `module.exports` to `exports`
- introduce `ts-node` to run importers so we can convert them to TS too

Lastly, sorry for this larg-ish PR, not my preference but when I tried
to reduce its scope, I would end up with mixed commons/esm that was even
more tricky to handle.

These files will be automatically recreated by `yarn build:api`,
`yarn build:browser`, and `yarn start:browser`, so we don’t need
them in the repo.

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Co-authored-by: Tom French <15848336+TomAFrench@users.noreply.github.com>