Bump the API version for the packaging APIs and Apps

**Describe the problem/challenge you have**
All of the CRs provided by kapp-controller are currently versioned `v1alpha1`. According to the [k8s API versioning guidelines](https://github.com/kubernetes/community/blob/master/contributors/devel/sig-architecture/api_changes.md#alpha-beta-and-stable-versions), they should all actually be versioned `v1beta1`.

**Describe the solution you'd like**
Bump the api versions to `v1beta1` to better align with k8s versioning practices

**Anything else you would like to add:**
No

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