multiarch updates

[rpunia1]

Description

This PR adds preliminary work for building multiarch images

• distroless base images have been updated to be multiarch (distroless-docker, distroless-with-utils-docker).
• certgen & kubectl images are also updated to be multiarch.
• Cloudbuilder CI build is updated to build/publish multiarch images for above ^
• some 3rd party test images are also made multiarch (testrunner, http-echo, kennship-http-echo)

nightly tests runs:

https://github.com/solo-io/gloo/actions/runs/12162387255
https://github.com/solo-io/gloo/actions/runs/12142343463

CI changes

• with this PR multiarch images are build and pushed for images
  distroless-docker, distroless-with-utils-docker, certgen, certgen-distroless, kubectl, kubectl-dtstroless

Testing steps

export VERSION=1.18.0-rc3
export MULTIARCH=true

make distroless-docker -B
make distroless-with-utils-docker -B
make certgen-docker -B
make certgen-distroless-docker -B
make kubectl-docker -B
make kubectl-distroless-docker -B

Notes for reviewers

Checklist:

• I have performed a self-review of my own code
• I have commented my code, particularly in hard-to-understand areas
• I have made corresponding changes to the documentation
• I have added tests that prove my fix is effective or that my feature works

[github-actions]

Visit the preview URL for this PR (updated for commit c3f6250):

https://gloo-edge--pr10421-rav-multiarch-qui1uu1b.web.app

_{(expires Tue, 10 Dec 2024 16:12:01 GMT)}

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[sheidkamp]

Some comments

[sheidkamp]

Looks like the execution of this job is commented out above, would be good to see this succeed in a test run.

[rpunia1]

sorry missed this, execution commented out as in ?

[rpunia1]

/kick "re-run failed CI cloudbuild"

[nfuden]

I like it. I know there will be some follow ups but its a great start!