Prepare an AI GW version of tracing documentation

As we refer to [this document](https://developer.konghq.com/gateway/tracing/) now from some places in the AI GW 2.0 docs, we have to carefully adapt this content to the realities of AI Gateway.

Note: this is currently in a fast-follow milestone, but treat it as a ticket with the lowest priority within this effort.

Start by reviewing the tracing documentation at https://developer.konghq.com/gateway/tracing/ and the AI Gateway 2.0 documentation references that point to it. Adapt the content to AI Gateway realities, then verify that the resulting page is accurate for those references; this is the lowest-priority ticket in the fast-follow effort.

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