Use kapp config to orphan delete resources

**Describe the problem/challenge you have**
Currently if we want to remove resources from a kapp app, we have to either manually remove the kapp labels from the app or first add the orphan-delete strategy annotation to the resources and then delete them, thus requiring 2 deploys.

**Describe the solution you'd like**
We would want a way to specify which resources to be orphan deleted using the kapp config. This would help us in removing resources from a app in one deploy command only.

**Anything else you would like to add:**
This would be beneficial when a resource present in a package needs to be removed from the package (but not from the cluster) in a subsequent version of a package.

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No source files or tests are named. Start by tracing how kapp config is read and how resource deletion and orphan-delete annotations are handled. Done means a single deploy can identify resources to orphan-delete while leaving them in the cluster, including when they are removed from a package.

Written by the indexing model from the issue text.