P1-1277 - Implement tooling standards in js package

[SResok]

Context

• Implement our tooling standards in the js package
  • @yoast/babel-preset, eslint-config-yoast, @yoast/jest-preset and @yoast/browserslist-config

Summary

This PR can be summarized in the following changelog entry:

• Implements our new tooling standards in the 'js' package

Relevant technical choices:

• Use the transpiled code only on production build
  • Running the build command from the 'js' package on every file change when using i.e the watch command would negatively impact the development speed drastically.
• Removed jsSrc and cssDist from config/webpack/paths.js because they were unused.
• Decided to revert the Babel config after talking with Nolle. Seems simpler to just keep using Webpack.
  • Downside is that this picks up the Babel config in the root. However, the test still use the Babel config in the JS folder. Something to talk about at a later stage.
• Use versions instead of file in our root
  • File copies over at the time of install. Using a version makes it a symlink because of the workspace. That seems preferable, and a must if we work on the packages.

Test instructions

Test instructions for the acceptance test before the PR gets merged

This PR can be acceptance tested by following these steps:

• Testing Eslint
  • Navigate to packages/js and run yarn lint
  • Verify there are now 141 warnings
• Testing Jest
  • Navigate to packages/js and run yarn test
  • Verify Test Suites: 55 passed without any errors

Test instructions for QA when the code is in the RC

• QA should use the same steps as above.

QA can test this PR by following these steps:

• Check if grunt build, grunt artifact and yarn lint still work as expected.

Impact check

This PR affects the following parts of the plugin, which may require extra testing:

UI changes

• This PR changes the UI in the plugin. I have added the 'UI change' label to this PR.

Other environments

• This PR also affects Shopify. I have added a changelog entry starting with [shopify-seo], added test instructions for Shopify and attached the Shopify label to this PR.

Documentation

• I have written documentation for this change.

Quality assurance

• I have tested this code to the best of my abilities
• I have added unittests to verify the code works as intended
• If any part of the code is behind a feature flag, my test instructions also cover cases where the feature flag is switched off.
• I have written this PR in accordance with my team's definition of done.

Fixes P1-1277

[igorschoester]

CR & ACC ✅

Changed the approach after some discussion: no more babel build for JS package specifically. Due to it being the root JS.