Website update

Recently we updated our website. Content is almost the same with just a few minor tweaks here and there. But a lot of background changes:

• Updated the base Template to the newest version (which updates a lot of JS to newer, better and faster versions)
• Integrated a GDPR solution that works site independent (which is nice to not be asked on every website)
• Improved HTTPS handling (by using a Let’s Encrypt certificate)
• Improved email handling by adding a valid DMARC entry
• Improved website SEO setup (site individual metadata, sitemap.xml)
• Integrated Internationalization (no actual localization to any specific language currently)
• Added a PHP email send solution instead of the "mailto:.." link
• Automated and integrated CI with gitlab.
• added robots.txt as well as a 404 page.
• lots of mobile improvements

For the next update we work on a full German translation of the website, which likely will become the default at some point in the future.