Create Keptn Argo REST client

[mowies]

Goal

Deploy the Keptn REST API backend using normal k8s operator practices (reconcile loops) and add the corresponding feature flag to the KeptnConfig resource.

Notes

new feature flag in keptn config lifecycle operator deploys REST API based on feature flag API has a kube client with read/list permissions to all keptn resources (basically)

### Tasks
- [ ] https://github.com/keptn/lifecycle-toolkit/issues/3594
- [ ] https://github.com/keptn/lifecycle-toolkit/issues/3595
- [ ] https://github.com/keptn/lifecycle-toolkit/issues/3596
- [ ] Follow up
- [ ] https://github.com/keptn/lifecycle-toolkit/issues/3597

[Bharadwajshivam28]

@mowies Hey I would like to work on this feature integration

[github-actions[bot]]

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