Moving repos and tooling from Github to Gitlab

It is made a clear choice to adopt gitlab as a platform, and the documentation is updated accordingly. In particular: Integrate user management via Azure AD with SKA. see https://gitlab.com/groups/ska-telescope/-/saml This depends on interactions with SKA IT and it should be planned at PI planning.(this is a strech as it needs to be discussed with IT) Gitlab is the primary source of truth for our code development, where we have a mirror in place, we should reverse it and make it so that github becomes the mirror of a gitlab repo. Group badges are defined so that every project can expose information in a consistent way Skeleton projects are moved into group templates Readthedocs is updated accordingly