CI Schedules

I set up a CI pipeline that we could use to run the script automatically via Gitlab's schedule instead of on a local machine.

I also tried to implement the DOI blacklist (and separated title and doi blacklist files). Didn't have a chance yet to test it.

Mails are sent through the KIT SMTP server now, which doesn't require a password.

Main issue: the proxy module doesn't seem to work in the Docker I've been using. See: https://git.opencarp.org/openCARP/publications/-/jobs/14043 Proxy is disabled for now.