build/run-images: switch base to busybox+libc

```
kubernetes-bootstrap                               latest                f7319a2945f1        3 minutes ago       56.39 MB
kubernetes-kubelet                                 latest                bd89cfebb960        3 minutes ago       56.39 MB
kubernetes-scheduler                               latest                05e140fa86ce        3 minutes ago       56.39 MB
kubernetes-proxy                                   latest                a60a0603c99b        3 minutes ago       56.39 MB
kubernetes-apiserver                               latest                7268af915b2d        3 minutes ago       56.39 MB
kubernetes-controller-manager                      latest                ef7661dd1313        3 minutes ago       56.39 MB
kubernetes                                         latest                cbd25d7c708b        3 minutes ago       56.39 MB
```

This [base](https://github.com/progrium/busybox) include glibc, so no need for `-static` build.

Why this busybox and not the "official" one?

(https://registry.hub.docker.com/_/busybox/)