Support multiple deployments with shared database #2442
Description
Multiple Helm deployments should be able to connect to a shared database, but manage their own sessions. Sessions can only be managed by the instance that created it. When users connect to another instance, they should not be able to interact with the session.
The scheduler should only run in one instance, otherwise this might lead to conflicts. A special handling has to be added for termination of idle sessions since the job requires access to the correct instance cluster.
This can be used to test new clusters while preserving data integrity and allows migrations without interruption.