Eliminate the need for babel loader by supporting ES Modules natively

[andyearnshaw]

I have a Discord bot that I am E2E testing using cucumber-js. The bot runs on Node 14 LTS and does not use transpilation of any kind. The only thing I need @babel/loader is so I can write my tests using modern ES code. The additional config and requirement of Babel, as well as the other drawbacks such as having to debug with source maps, is a prime example of tooling getting in the way of writing code. Jest already has an experimental command line switch allowing native modules, and it should be easier for cucumber-js because I don't think a custom loader would be necessary.

From a cursory glance at cucumber-js's code, I think it should be relatively straightforward to get ES modules working with the following improvements, while retaining compatibility with older Node versions:

• Switch uses of require() in the codebase to await import(). import() can import Common JS modules, but require() cannot import ES modules.
• Introduce a second compile step from TypeScript to a version of JS compatible with Node 14 LTS
• Add a cucumber-esm.mjs file to /bin that imports and runs cucumber.

Is there anything I might have missed that would make this more complicated?

[davidjgoss]

Closing as a dup of #1304