Automatic merge from submit-queue. If you want to cherry-pick this change to another branch, please follow the instructions <a href="https://github.com/kubernetes/community/blob/master/contributors/devel/cherry-picks.md">here</a>.
First pass of cert list
**What this PR does / why we need it**:
Refactors the cert management code in kubeadm to be more extensible and resiliant.
This initial change doesn't change anything on the surface, and in fact appears to add a bunch of complexity. The goal here is to reduce duplication in the certs codebase, which is started in this PR by gutting the New*CertAndKey. Eventually, those functions will be removed altogether. The declarative list will also allow us to build a more explicit renewal function and command line interface and reduce much more duplication in the cert package.
**Special notes for your reviewer**:
**Release note**:
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