Add readiness and liveness probes in controller

[ywluogg]

Add readiness and liveness probes in controller.
Closes #3111 and #1586.

The reason for adding the two probes are discussed in PR #3349.
Optional considered methods: using https-metrics ports. Current method is chosen based on discussions in PR #3349.

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Add readiness and liveness probes in controller.

[afrittoli]

Thanks for this!
/approve

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[ghost]

/lgtm

[ywluogg]

/retest