Simplify evacuate code

[soltysh]

Currently our oadm manage-node --evacuate code is filled with all sorts of controller checks to make sure we properly identify pods during node evacuation. We should ensure all controllers have controllerRef set (as proposed in kubernetes/kubernetes#24946) to be able to have a generic code in the evacuation.

@mfojtik fyi

[mfojtik]

@soltysh the old servers will not have that annotation set, so we will always need to carry the "legacy" code in case not all pods respects that annotation.

[soltysh]

First we need to make sure ALL controllers set this annotation accordingly, once that is done we'll have to do version dependent logic. Since, old clusters won't have all the resources you were adding in your PR, either.

[smarterclayton]

We need to move people to using drain and deprecate and remove --evacuate.

[mfojtik]

@smarterclayton PR opened.