Improve values schema

[TylerHelmuth]

Works towards #135

This PR defines all the properties for opentelemetry-collector's values.schema.yaml. Actual validations to follow.

[TylerHelmuth]

The amount of changes kinda got away from me. Let me know what you think and if I should go an add actual validations to this PR as well or if I should make it smaller instead.

[dmitryax]

Let me know what you think and if I should go an add actual validations to this PR as well or if I should make it smaller instead.

What actual validation do you mean? Isn't it enforced already?

[TylerHelmuth]

Let me know what you think and if I should go an add actual validations to this PR as well or if I should make it smaller instead.

What actual validation do you mean? Isn't it enforced already?

The requirement for having at least one of standaloneCollector or agentCollector enabled is already present. I was going to review and see if there were any other scenarios. There may not be.

[TylerHelmuth]

Looking through the only other validation I could come up with was something fancy around standaloneCollector.enabled and podDisruptionBudget/autoscaling, but I think all that matters is that enabled is required by the properties. The actual value of enabled doesn't matter. So I think this PR gets the schema into a good state to validate the current values.yaml.

[dmitryax]

Looking through the only other validation I could come up with was something fancy around standaloneCollector.enabled and podDisruptionBudget/autoscaling, but I think all that matters is that enabled is required by the properties. The actual value of enabled doesn't matter. So I think this PR gets the schema into a good state to validate the current values.yaml.

I don't think the fancy validations are that important to have. My idea is that we need to define all the properties with "additionalProperties": false in order to make sure that any replacements of the existing configuration parameters blocks the chart upgrade. It makes any breaking change at least not silently breaking.

[dmitryax]

LGTM