Sync package maintainers to a gitlab group to support upcoming "git packaging sources"

We will move to storing all packaging sources in git soon as announced here.

Per the announcement all package maintainers must gain write access to: https://gitlab.archlinux.org/archlinux/packaging/packages. This can be archived by either adding all package maintainers directly to the group or perhaps (inspired by #5) add them to https://gitlab.archlinux.org/archlinux/teams/devs and https://gitlab.archlinux.org/archlinux/teams/tus.

The group names in Keycloan are defined here.