test: Introduce the Helm Chart Toolbox integration tests

[petewall]

Use the Helm Chart Toolbox to run Helm chart integration tests in parallel. Starting with two tests that I found in the ci directory.

Where I'd take this next:

1. Copy the abc_values.yaml files from the ci directory into the individual test directories. This will keep them in the text directory and "associated" with that test.
2. Create new tests at least to cover the existing tests run in ci
3. Stop using chart-testing (aka ct), which is what runs tests sequentially and takes a long time.

At this point, you should see the helm-ci GitHub Action take ~5 minutes, rather than 20+ minutes.

4. Long-term phase: Split the tests to focus on individual features, rather than packing lots of things into a small amount of tests. Since Helm Chart Toolbox tests will run in parallel, a larger count of smaller tests is better than a handful of complicated tests.
5. Create more tests!

[CLAassistant]

All committers have signed the CLA.

[github-actions]

Helm Diff Output - Summary

Default Values Scenario-diff-output

Distributed Scenario-diff-output

Ingress Values Scenario-diff-output

Legacy Monitoring Values Scenario-diff-output

Simple Scalable AWS Kube IRSA Values Scenario-diff-output

Simple Thanos Values Scenario-diff-output

Single Binary Scenario-diff-output

[jkroepke]

@petewall does it include https://github.com/helm-unittest/helm-unittest?

[petewall]

This doesn't include helm unittest. That project rules and stays on its own. Helm Chart Toolbox is something I started to handle making actual cluster-based tests easier and can run in parallel.