feat(nodejs): configureAwsInstrumentation for downstream

[mzl-md]

Enables downstream repos to configure @opentelemetry/instrumentation-aws-sdk using the global function configureAwsInstrumentation(). This is required for setting custom user attributes as described in the documentation.

[linux-foundation-easycla]

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• ✅ login: mzl-md / name: Martin Schumacher (6ada9e2, 8a383c0, 38bba7b)

[tylerbenson]

Would you mind adding a unit test to validate this code path is working properly and doesn't have regressions in the future?

[mzl-md]

Currently there are no unit tests at all. Setting up a test framework is not really the scope of this PR.

Also, I can't find a good way to do this. Sinon fails to stub registerInstrumentations() or the constructor of AwsInstrumentation and I see no other way to check what arguments are passed to AwsInstrumentation. I added a trivial test that checks if the global function is called, but I think that is not really helpful.

In my opinion, meaningful tests require restructuring the wrapper.ts in separate files.

[tylerbenson]

That's a reasonable criticism. I'd love to see contributions to help us improve testing across each language, but I understand that's not reasonable scope in a PR like this. I appreciate you making an effort to at least add something.