feat(namespaces): add values schema

[voidus]

Heya,

I spent more time than I'd like to admit debugging and ultimately found out my values shape was wrong, so I thought I'd propose this change.

Version bumped since some values that worked before will now fail to validate, not sure if that aligns with your plans.
I also added a version of this without the tests if you'd prefer to merge this without them: #1173

[morremeyer]

This is a great addition, thank you!

Thinking of the testing as also a good one, but I think we can even simplify that:

The CI already runs helm lint with the chart-testing tool, so all the tests for valid files can be moved to a *-values.yaml in charts/namespaces/ci.

I'm inclined to say that we don't necessarily need tests for invalid values, since the positive testing for valid values should cover most error cases easily. This would have the benefit that we'd be reusing the already existing workflows and we'd have one less script to maintain.

What do you think, @voidus?

[voidus]

I'll trust your judgement regarding the testing, I don't have enough experience to say how useful/annoying this will be during maintenance etc, but I guess the schema is unlikely to change anyways.

I added it because I wanted invalid configs to be flagged, so I added a test that shows me it actually does. But that doesn't mean they need to end up in the codebase long-term.

[morremeyer]

Then I'd like to move the valid test files to the *-values.yaml naming in the ci directory, and the invalid files and the script can be removed.

That has the best tradeoff between maintenance effort and improved validation in my eyes.