Improvement: Stop using "latest" for any dependencies

Summary

(Summarize the bug encountered, concisely as possible)

Steps to reproduce

Deploy. See :latest used.

Current behavior

Dependency on busybox:latest @ Docker Hub. Floating version of GitLab KAS.

Expected behavior

Dependency on a specific version of:

• busybox, such as busybox:1.33.0
• kas https://gitlab.com/gitlab-org/cluster-integration/gitlab-agent

Versions

• Chart: current

Actionable

• gitlab/kas uses :latest
• busybox:latest is used in initContainers