Use busybox for cleanupProxy image

Feature Request

Why

We should be able to use an existing community image (like busybox) to perform the cleanupProxy actions.

Proposed Solution

Use the alpine container image in values.yaml:

cleanupProxy:
      image:
        registry: registry1.dso.mil
        repository: ironbank/opensource/alpinelinux/alpine
        tag: 3.19.1
        sha: ""
        pullPolicy: IfNotPresent

and update the job-patchWebhook.yaml:

- name: cleanup-proxy
  command:
  - /bin/sh
  - -c
  - |
    until wget --spider -q http://localhost:15021/healthz/ready; do echo \"Waiting for Sidecar...\"; sleep 3; done;
    echo \"Sidecar available, sleeping 10 seconds then killing istio proxy...\";
    sleep 10;
    x=$(echo $?); wget --post-data='' -qO- http://localhost:15020/quitquitquit && exit $x