[exporter/datadog] Expose source provider

[mackjmr]

Description

The goal of this PR is to expose the GetSourceProvider method from hostmetadata, which is currently under an internal folder in datadogexporter.

In order to do so, we create new package github.com/open-telemetry/opentelemetry-collector-contrib/pkg/datadog/hostmetadata which calls on internal hostmetadata's GetSourceProvider.

We also create new module github.com/open-telemetry/opentelemetry-collector-contrib/internal/datadog, where we store the internal hostmetadata, clientutil and scrub packages. We move hostmetadata there as it needs to be imported in both datadogexporter, and pkg/datadog/hostmetadata, and we move clientutil and scrub there as they are imported by hostmetadata.

Link to tracking issue

Fixes

Testing

Documentation

[songy23]

This warrants an API changelog too

[mackjmr]

CI failures will be solved once #37499 is merged

[mackjmr]

We already have pkg/datadog, why create internal/datadog rather than reusing pkg/datadog?

@songy23 If we only use pkg/datadog, then we need to expose 10-15 funcs/types from clientutils / scrub / hostmetadata so they can be imported in datadogexporter. Creating internal/datadog allows us to keep them fully internal, and be able to import them in both pkg/datadog/hostmetadata and datadogexporter. It reduces surface API + need to create "exposed" packages for both clientutils / scrub.

[songy23]

need to run make generate and fix lint

[songy23]

I believe you need to add metadata.yaml to internal/datadog, like this one http://github.com/open-telemetry/opentelemetry-collector-contrib/blob/main/pkg/datadog/metadata.yaml
then run make generate again

[mackjmr]

Thanks @songy23, added metadata.yaml. I think this is all thats needed, because there is no changes after make generate

[songy23]

verifyAllModulesInSet failed: Module github.com/open-telemetry/opentelemetry-collector-contrib/internal/datadog (defined in /home/runner/work/opentelemetry-collector-contrib/opentelemetry-collector-contrib/internal/datadog/go.mod) is not listed in any module set.

[songy23]

You're still missing something (not sure what exactly is missing). make generate should have added internal/datadog to http://github.com/open-telemetry/opentelemetry-collector-contrib/blob/main/.github/CODEOWNERS but currently it is not present

[mackjmr]

Yeah, noticed that. Will try running make generate agaiin

[mackjmr]

@songy23 make generate didn't add it, so i added manually