Add guidance about documenting third-party products

[imatwawana]

The following question was raised in the October 17, 2024 style roundtable:

What is the best practice for documenting third party products (AWS, GCS, etc.) How much can/should we document for how our products integrate with our most common partners?

From Fiona:

tricky question, but I think the answer falls into the bucket of how we document other OSS products - like Prometheus

We document our usage of them, but we do not document them

So, we should avoid referring to [third party products] as we cannot control that content and it would potentially become wrong, exposing us to issues with our MSA.

Wherever possible, we should structure the documentation so that we can link to the right location where we that product has its documentation as it is that vendor's job to maintain their docs

"We don't document other company's products" which seems pretty obvious, but can be subtle given how woven our products are