Allow disabling non-necessary kubelet and apiserver endpoints

This adds flags to disable various endpoints on the kubelet server that aren't essential to its core function. 

This could also be achieved by putting it behind a proxy, so these are purely for convenience; let me know if it's undesirable to have this built into the kubelet.
I'm really sorry, I should have noticed this earlier-- I think this is a helper function for testing, and as such, you don't need to add this parameter and pass false everywhere.