Build pipeline for deployment on DESY server

@paul @sophie.servan

In order to deliver this page to the (currently being set up) DESY-hosted web server, there needs to be

1. a build pipeline here in this repository, which could probably be almost 1:1 the same as in hifis.net
2. a deployment script on the webserver running with Paul's rights, to regularly pull the newest artifacts. I handcrafted that and could add it as a snippet here