[Dashboard] Cache the kubectl list responses

[pablotp]

Summary

Implement a cache to reduce the kubectl calls needed to show the list of rollouts.

Use Cases

When there are many deployments in the same namespace, the kubectl list commands can take a long time to complete. A cache will improve the user experience when loading the list of rollouts, and it will reduce the load in the control plane.

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[pablotp]

PR with a suggestion on how to implement this: #4250