Docusaurus upgrade 3.3.2

[Mko13]

This PR is to upgrade Docusaurus from v2.2 to v3.3.2.

We tested locally (basic checks) on:

• Ubuntu 22.04 LTS
• MacOS (Sonoma)

Verifying entire contents of the https://docs.robotframework.org/docs/style_guide is difficult, we need help in reviewing the pages from current contributors and volunteers 🙂 (mainly layout and formatting).

It's easier to review this PR commit-by-commit.

---

To clean install and test:

• Clone the repo
• Checkout current branch
• Go to thewebsite/ directory:
• Run
  npm ci (See: https://docs.npmjs.com/cli/v10/commands/npm-ci)
• If everything goes well, check the Docusaurus version
  npx docusaurus -V (should get 3.3.2)
• npm start
• Now you should be able to view the docs in your browser: http://localhost:3000.

[guidodemmenie]

Tested on:
MacOS Version: 13.6 (22G120)