ResourceConfig#customResourceDefinitions field/config seems to be no longer needed

[manusa]

Description

Seems there are no longer usages of that field.

• https://github.com/eclipse/jkube/blob/efe3e902ea9ef571be5c32839cfa64321908aa18/jkube-kit/config/resource/src/main/java/org/eclipse/jkube/kit/config/resource/ResourceConfig.java#L77
• https://github.com/eclipse/jkube/blob/cf88735616f98ca48b03c756ba5741bf0c92ce8c/quickstarts/maven/spring-boot-crd/pom.xml#L82-L83

[abhijeetshuklaoist]

Hey @manusa Please assign it to me, I will work on it.