Make newClientsetManager in k8s service public

[sbansal7]

Description
I am trying to define additional k8s apis in my gateway, and trying to reuse as much code from clutch as possible. However, since this newClientsetManager is not public, I had to copy the entire file. It will be great if this can be made public.
Expected Behavior
The function is renamed to NewClientsetManager to make it public
Actual Behavior

Currently, the function is private, so I have to copy the file to make use of functionality in the extension.

Version

Other Context