SYS-671 prune disused clutter

[instantlinux]

Summary of Changes

Nine years of evolution has left a considerable amount of content that is no longer used. These are being removed:

• The stacks directory, once used for Docker Swarm -- retired in favor of Kubernetes
• The wxcam-upload image -- worked for Weather Underground webcam support until IBM retired the service in 2021
• An experiment with dex for k8s authentication -- opted for Keycloak instead
• Comment out contents of k8s/global.yaml as first step of eliminating the file

Also, helm 4.1.0 is out; this phases out helm 3.19.2.

Why is this change being made?

Dead code is a distraction that could waste time for those encountering this repo in the future.

How was this tested? How can the reviewer verify your testing?

Local testing.

Completion checklist

• The pull request is linked to all related issues
• This change has unit test coverage
• Documentation has been updated
• Dependencies have been updated and verified