Make use of server side apply to reduce conflicts

[johscheuer]

What would you like to be added/changed?

We should look into using server side apply to reduce the conflicts that we see when updating the status of our resources. This means we have to change the Update status calls to use the appropriate Patch calls. We want to run some additional tests before merging this and we want to have a feature flag on the operator to enable/disable this feature (default should be false to match the current behaviour). We probably also have to adjust our Kubernetes mock to support the Patch call.

[johscheuer]

Docs: https://kubernetes.io/docs/reference/using-api/server-side-apply/