New Tools page: GitLab VU for researchers

[Elisa-on-GitHub]

This concerns the GitLab for researchers instance, that is managed by the University Library. This should become one of the standard tools pages.

Connected to #613

[Elisa-on-GitHub]

I will try to get this done during the hackathon on 7 July

[Elisa-on-GitHub]

Dania is working on this. See #830