Use a Deployment instead of a StatefulSet for the controller

[antonipp]

Description

While trying out the agent-sandbox project, I noticed that the main controller is deployed as a StatefulSet. I couldn't really find a justification for it in the commit history, so this looks like an oversight. The controller is stateless and doesn't require a stable network identity, so I don't really see a reason to use a much heavier abstraction here. Moreover, STS ordered rollout semantics are unnecessary for a stateless controller and could complicate scaling/updates if leader election is enabled for HA.

So my PR switches the controller to be deployed as a simple Deployment, I think it will make operations easier for everyone

[k8s-ci-robot]

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This pull-request has been approved by: antonipp
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Hi @antonipp. Thanks for your PR.

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