Introduce values schema for the collector chart

[dmitryax]

Introduce values.schema.json for values.yaml input validation in opentelemetry-collector helm chart. All the objects in values.yaml with predefined set of properties should not allow unknown properties.

This is a preliminary step for any big change to the helm chart configuration, e.g. #91

The following schema can be used as a reference: https://github.com/signalfx/splunk-otel-collector-chart/blob/main/helm-charts/splunk-otel-collector/values.schema.json

[TylerHelmuth]

I can look at this.

[TylerHelmuth]

There is a lot of schema to add. Will probably submit PRs in small chunks to make review easier since each bit of validation added is valid in itself.

[dmitryax]

There is a lot of schema to add. Will probably submit PRs in small chunks to make review easier since each bit of validation added is valid in itself.

Sounds good. Thanks!