Kubernetes should configure `ingress.class` and `storage.class`

Today we use configuration for ingress class and storage class on a stack level `configure` hook. We have to copy again and again same code. So stop doing that there is a proposition to move this code into the `kubernetes/configure` extension with following behaviour

## Ingress Class

Executed if and only if user defined they want to read ingress class from variable `KUBERNETES_INGRESS_CLASS` then

- [ ] Extension list currently available ingress classes.
- [ ] Extension asks user to choose one from listed
- [ ] Extension uses as auto-complete default ingress class otherwise first
- [ ] If no ingress classes configured in the Kubernetes user get warning message
- [ ] User can enter empty value (random - never)
- [ ] If not empty extensions validates presence of ingress class

## Storage class

Executed if and only if user defined they want to read storage class from variable `KUBERNETES_STORAGE_CLASS` then

- [ ] Extension list currently available storage classes.
- [ ] Extension asks user to choose one from listed
- [ ] Extension uses as auto-complete default storage class otherwise first
- [ ] If no ingress classes configured in the Kubernetes user get warning message
- [ ] User can enter empty value (random - never)
- [ ] If not empty extensions validates presence of storage class

Start with the kubernetes/configure extension and the existing stack-level configure hook that handles KUBERNETES_INGRESS_CLASS and KUBERNETES_STORAGE_CLASS. Trace how available Kubernetes classes are listed, selected, defaulted, warned about, and validated. Done means both behaviors live in the extension and the duplicated stack-level configuration is no longer needed.

Written by the indexing model from the issue text.