Review image ks-guestbook

Why
The test appManagement is using a container image that is only available to x86_64 architecture, therefore the test fails in IBM P and Z platforms.
Moreover, this current image being in use is stored in the GCR's registry, with an account out of our control.

What
We need to substitute the x86_64 container image from these lines:

• https://github.com/argoproj/argo-cd/blob/master/test/e2e/app_management_test.go#L950
• https://github.com/argoproj/argo-cd/blob/master/test/e2e/app_management_test.go#L961
• https://github.com/argoproj/argo-cd/blob/master/test/e2e/app_management_test.go#L972

by a multi-arch image stored in a public quay.io account.

Acceptance Criteria

• A new multi-arch image with the same functionality ks-guestbook-demo
• A PR in the upstream project to amend the code