Don't inline Worker and WASM when building ESM

[bminixhofer]

As mentioned in https://github.com/bminixhofer/tractjs/blob/master/README.md#what-about-size not inlining the Worker and WASM would reduce size. With the recent changes in the build system this should be much easier than before.

At the moment the WASM is actually doubly inlined, once in the worker.js, then the worker.js is again inlined in tractjs.js. The WASM itself is only 4.7MB (1.0MB gzipped) so fixing this would reduce the size by roughly 50%! But it is of course only possible for the ESM build, not for tractjs.min.js.

The CJS build for Node.js will also still be inlined (for now) since size is not as big of an issue for Node applications and I don't want to get into any file system issues.