Remove log4j-kubernetes module

[ppkarwasz]

The log4j-kubernetes module is problematic, because:

• the kubernetes-model-core dependency follows Kubernetes lifecycle. It might be (and it already occurred) that breaking changes occurred on a minor version change,
• on the other hand it depends only on StrLookup, which is unlikely to ever change,
• the Fabric8 team has a better idea, which properties could be interesting to users.

Therefore if fabric8io/kubernetes-client#5718 is accepted, I propose to remove log4j-kubernetes from our codebase.

[ppkarwasz]

An improved kubernetes-log4j module is available since Kubernetes Client version 6.11.0 (cf. announcement), therefore we can remove log4j-kubernetes.