Add `enable_mr_pipelines` CI input to match other AST-based CI components
Some changes have been made regarding e-mails sent from this instance.
E-mails are now sent from automatedservices@dn0.eu through the service Sweego. Due to an issue with the previous e-mail provider, the past few days of notifications are now only visible within the GitLab interface itself.
Add `enable_mr_pipelines` CI input to match other AST-based CI components