Revert back to using kubectl in channels

[olemarkus]

I think it will take a while to get the custom client production grade. Reverting to 1.24 behavior so that we get working tests and that this does not block any release.

Introduces an Applier interface and keeps the custom client based implementation.

[justinsb]

I'd really like to try to get this working - I am going to see about OSSing the code we have or reproducing it today!

That said, I do think an interface makes sense here.

[olemarkus]

What do you think about merging this and then do another PR for switching back. Or using tags for switching implementation if we want to (feature flag could make sense, but it would take a lot more to implement and propagate through nodeup)

[justinsb]

Yes, I think that's a good plan @olemarkus - thanks for suggesting it!

[justinsb]

/approve /lgtm

[k8s-ci-robot]

[APPROVALNOTIFIER] This PR is APPROVED

This pull-request has been approved by: justinsb

The full list of commands accepted by this bot can be found here.

The pull request process is described here

Needs approval from an approver in each of these files:

• ~~OWNERS~~ [justinsb]

Approvers can indicate their approval by writing /approve in a comment Approvers can cancel approval by writing /approve cancel in a comment