CI: Build auto-pause-hook for all architectures

[spowelljr]

Before, running make push-auto-pause-hook-image would only build the auto-pause-hook for the arch of the machine running the command on. Modified the Dockerfile and Makefile target to build an image for each architecture.

Also updated the Dockerfile to a multi-step build so the base image is from scratch instead of golang. Resulting in the image going from 790MB to 45MB, greatly increasing the speed of enabling the addon for people with slow internet speeds.

Before:

REPOSITORY                            TAG                        IMAGE ID       CREATED          SIZE
gcr.io/k8s-minikube/auto-pause-hook   v0.0.4                     a633c3ce5969   9 months ago     790MB

After:

REPOSITORY                            TAG                        IMAGE ID       CREATED          SIZE
gcr.io/k8s-minikube/auto-pause-hook   v0.0.5                     37295df93934   2 months ago     45MB

[k8s-ci-robot]

[APPROVALNOTIFIER] This PR is APPROVED

This pull-request has been approved by: medyagh, spowelljr

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[medyagh]

as part of this PR we should ensure the image is pushed

[spowelljr]

The image is pushed

$ docker pull gcr.io/k8s-minikube/auto-pause-hook:v0.0.5
v0.0.5: Pulling from k8s-minikube/auto-pause-hook
6c99d14f8e2e: Pull complete 
Digest: sha256:d613ed2c891882b602b5aca668e92d4606a1b3832d96750ab25804de15929522
Status: Downloaded newer image for gcr.io/k8s-minikube/auto-pause-hook:v0.0.5
gcr.io/k8s-minikube/auto-pause-hook:v0.0.5