feat: add hero homepage overlays

[doriengr]

Closes #49

Testing:

1. As soon as the page is opened for the first time, the overlay is opened automatically. A card should appear that says something about the project, but can also start the animation.
2. Check if the animation can be started from the welcome card
3. Click through the popups and close the overlay
4. Click the button in the hero to start the animation again. Check if everything works as expected.
5. Reload the page and check, if the welcome-overlay is not started again. The cookie green_ecolution_initial_load should now be set.
6. Start the animation again over the button in the hero section.

Testing Edge cases:

1. Delete the cookie if it is currently set. Open the website with a screen size of less than 1280px and check that the cookie is not set. Also check, that the animation is not started.
2. Open the site again with a screen size larger than 1279px. Check if the animation is started. Than resize the screen size to a mobile width and check if the animation is hidden.
3. Reload, scroll down and check if the website is scrolling up automatically after the animation is started.

🙏

[github-actions]

Deployment of PR #56 successful 🚀

You can access the deployment at pr-56.website.dev.green-ecolution.de to review the changes 👀

⚠️ Please note that this deployment is temporary and will be deleted after the PR is closed.

[choffmann]

@doriengr I noticed a small issue when the first dialog box appears and I click outside it. The animation stops and the dialog is still visible

[choffmann]

👍