Build Tools: Configure prettier properly.

[youknowriad]

When working on the package update ticket/PR I mistakenly overwrote the webpack config file styling by using prettier. It turns out that WordPress Core is not defining the right prettier config, even if it has prettier in its dependencies.

Trac ticket: https://core.trac.wordpress.org/ticket/60316

The config has just been copied from Gutenberg Repo.

Testing instructions

• Open VSCore and have the prettier extension installed
• Open any js file (like webpack.config.js)
• Format the file
• Prettier should use the right prettier config

[swissspidy]

Related: #31823

Does adding the Prettier config cause any accidental changes to existing files which may not yet 100% adhere to coding standards?

[youknowriad]

In 57330:

Build Tools: Configure prettier properly.

Allows tools like prettier or VSCode to auto-format JS files propertly.
It pulls the prettier config that is used in the Gutenberg repository.

Props gziolo.
Fixes #60316.

[youknowriad]

Does adding the Prettier config cause any accidental changes to existing files which may not yet 100% adhere to coding standards?

Well I added it because I had accidental changes caused by me formatting files in Core. So in that sense, Core already had a prettier config (as it had prettier as a dependency) but it was just using the default one. Adding this reduces the risk of accidental changes.