Add initial lifecycle and hooks into kubelet.

My suggestion is to add a timeout to the function calls, with the expectation that after that time the functions will return with an error. I'm being picky about this because you really need to pass the timeout down into the script you're calling as a parameter. I don't care if you implement in another PR, but I think the timeout really deserves to make it into the interface for the first cut, because it's really very important.