from an approach that loaded the runners only once at the startup
to a method that will be repeated i.e. if the Nomad Event Stream connection interrupts.
that was caused by creating an intermediate environment `fetchedEnvironment` when fetching the environments but not removing it in case that we just copy its configuration to the existing environment.
In today's unattended upgrade, we have seen how the prewarming pool size dropped to (near) zero. This was based on lost Nomad allocations. The allocations got rescheduled, but not added again to Poseidon.
The reason for this is a miscommunication between the Event Handling and the Nomad Manager. `removedByPoseidon` was true even if the runner was not removed by the manager, but an idle runner.
