Upgrade ArangoDB 3.11 -> 3.12

Blocked by task https://gitlab.com/nodeum.org/bwSFS-2/bwSFS-2-repo/-/issues/99 that has to be performed before (on all deployments)

• Upgrade ArangoDB 3.11 -> 3.12 (Upgrades have to be gradual, 1 GA version at a time as per https://docs.arangodb.com/stable/operations/upgrading/#upgrade-paths)