Feat: Kubectl get implementation

[yue9944882]

ideally i think this can be a replacement for GenericKubernetesApi

[brendandburns]

This is going to get messy/confusing to people because:

Kubectl.get().namespace(foo).name(bar).execute() will work, but Kubectl.get().name(bar).namespace(foo) won't.

I think we should either get rid of this class and merge the execute methods, or make this class extend from KubectlGet

[yue9944882]

Kubectl.get().namespace(foo).name(bar).execute() will work, but Kubectl.get().name(bar).namespace(foo) won't.

yeah i agree this can be confusing to the users. while the point here is that we're returning single object upon specifying resource name, and return a list of objects if the name absent. java doesn't support multi-return or overriding return type for the execute method so merging or overriding the execute methods won't work..

in a word, if we're to make both namespace(foo).name(bar) and name(bar).namespace(foo) work, the execute method will have to return a list of object even when getting one object, which can be even more confusing i suppose?

[brendandburns]

Hrm, why not just have, and then you can do:

return new KubectlGetSingle().namespace(namespace).name(name) in the function that adds the name, then it will work either way.

public KubectlGetSingle<ApiType> extends ResourceBuilder<...>, implements Kubectl.Executable<ApiType>

[yue9944882]

done

[brendandburns]

Generally looks good, one comment about the interface.

[brendandburns]

/lgtm
/approve

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