Don't hardcode http as the protocol when using GitLab

The line https://gitlab.software.geant.org/nmaas/nmaas-platform/-/blob/develop/src/main/java/net/geant/nmaas/externalservices/gitlab/GitLabManager.java#L63 hardcodes http for accessing Gitlab. This works fine if the Gitlab is in the same Kubernetes cluster and communication is via the Kubernetes overlay network. However, this does not work with external GitLab instances where HTTPS is unavoidable.

To upload designs, you'll need to enable LFS and have an admin enable hashed storage. More information