Reorganize quarkus-kubernetes source

[iocanel]

Description
At the moment we have a single processor (KubernetesProcessor)to generating resources for:

• kubernetes
• openshift
• knative

As we add more features, the processor grow larger and harder to maintain.
I would like split the processing of kubernetes, knative and openshift into different processors that integrate with each other.

Implementation ideas
We could expose create build items for dekorators and configurators (in the spi).
We could have a central processor that would apply configurators and decorators and a processor per platform that would generate those.

[iocanel]

This can be closed now that #12655 is merged.