Automatic Cleanup for PREvant tiles

[AnumDastgir]

PREvant allows us to instantiate individual environments very quickly. While this being a great feature, these easily created environments can easily be forgotten, thus causing an issue of draining and running out of resources at the hosting system.

To overcome this issue, an automatic cleanup for those unwanted environments is needed, so that if they're not being used, they should release the occupied resources automatically. Therefore, we consider following implementation plan:

1. PREvant should gather OpenTelemetry metrics from Traefik (more specific, HTTP metrics) to check if applications' routes haven’t been accessed in recent.
2. The least used applications will then be backed-up in database, e.g. the Kubernetes YAML manifests of application, and the applications will be deleted the infrastructure, except persistent volumes
3. The application can be restored from the database and deployed with the preserved persistent volumes
4. If the applications haven't restored from database in a period of time, the database and existing persistent volumes will be cleaned up

[harridu]

Please also consider to not restart the environments on a reboot. Esp for using Docker you have to wait ages at boot time, till all containers are running again.

[schrieveslaach]

I'm considering that this deletion should be more sophisticated once PREvant is able to collect metrics of the hardware utilization (see #201) so that things get cleaned up when the backend (K8s or Docker) hardware utilization reaches a certain threshold.