descheduler operator: deploy operator image built in PR CI job in e2e

Right now there's no e2e for testing the descheduler operator. We need to deploy the operator inside a cluster through a deployment so we test what we run in the production.

This way any change made to the operator gets tested as part of a PR.

Acceptance Criteria:

• the descheduler operator is deployed from a PR built image.
• basic eviction use cases are tested (e.g. pod exceeding pod lifetime)