Automatic merge from submit-queue (batch tested with PRs 35408, 41915, 41992, 41964, 41925)

Standard Debian base image

**What this PR does / why we need it**:

The goal of this new image is to provide a standard base image for Kubernetes system images that require substantial external dependencies (e.g. kube-proxy and fluentd). The image is significantly reduced from the standard `debian:jessie-slim` image (40 MB vs 80 MB), and removes a number of unnecessary dependencies such as e2fsprogs, systemd, and sysv-rc. In the future we may consider further reducing it to the bare minimum to run the package manager, with the requirement that images based on it add all the dependencies they need.

I tested this by rebasing kube-proxy on this image and running the e2e tests. I'm targeting 1.6 for rebasing kube-proxy & fluentd on this.

For the rational behind basing on Debian, see https://github.com/kubernetes/kubernetes/issues/40248#issuecomment-280781931

Largely based off [debian-iptables](https://github.com/kubernetes/kubernetes/tree/master/build/debian-iptables/) and [ubuntu-slim](https://github.com/kubernetes/ingress/tree/master/images/ubuntu-slim).

**Which issue this PR fixes**
https://github.com/kubernetes/kubernetes/issues/40248

**Special notes for your reviewer**:
@luxas Please review the qemu cross-build logic in the Makefile. It's copied from [debian-iptables](https://github.com/kubernetes/kubernetes/blob/master/build/debian-iptables/Makefile), but I'm not sure exactly what it's doing.

/cc @jessfraz @dlorenc