Refactor automated lighthouse scans

[MarcelKnobelsdorf]

✨ Refactor: Lighthouse scans

The Lighthouse scan runs automatically after each push or manually.
That should be changed, because we need to await the deployment process, before running the lighthouse tests.
Additionally, the paths that shall be tested need to be listed in lighthouse.yml. With the new blog feature, that should be automated, to include the latest blog posts as well.

Acceptance criteria

• Lighthouse scans should include all deployed paths automatically
• The Lighthouse scans should be run after each successful deployment

Hint

https://github.com/treosh/lighthouse-ci-action#mainyml-7