Add GitHub Action for Build & Deploy

[tbreuss]

Add a GitHub action to build and deploy the website.

Building:

• See Eleventy website

Deploy:

• Must support transfering artefacts to a normal (shared) hosting (i.e. via SCP command)

A step by step tutorial could be found here: https://dev.to/koddr/automate-that-a-practical-guide-to-github-actions-build-deploy-a-static-11ty-website-to-remote-virtual-server-after-push-d19

[tbreuss]

Done