Usability improvement of Kubernetes service

[ivakoleva]

What is the feature request? What problem does it solve? VDKCS service for Kubernetes API communication needs usability improvement.

Suggested solution

1. move KubernetesService to dedicated kubernetes package
2. to simplify -> extract nested classes (JobStatus, JobStatusCondition, Resources, Probe, JobExecution, ContainerResourceType)
3. for readability -> cleanup redundant private final field modifiers from @Value-annotated classes
4. move to dedicated functions the content of afterPropertiesSet(), for example populateApiClient(), validateDataJobTemplate(), etc.
5. what is health() unused method?
6. organize the API surface -> group fields,getters/setters,contructor,methods by non-static/static then access modifier by public/package default/protected/private
7. the sort the public group entries by logical purpose -> for example mark //namespace section then place createNamespace() then deleteNamespace(), mark //cronjob section then place listCronJobs(), readCronJob(), createCronJob()
8. sort non-public group entries by purpose
9. sort static public/non-public methods
10. move static final fields to extending classes/util, based on usages
11. refactor fromInteger and fromDateTime -> transform to (final) functions, eventually move to (final) utilities to reuse (JobStatus, JobStatusCondition, Resources, Probe)