Adding OTel grpc logger to Product Catalog

[kerneljack]

Changes

Added OTLP Logs to the Product Catalog service, using the slog logger.

I wasn't sure whether "attributes" on the log output are desirable so I've left an example in the code on line 279. If this is too verbose and we don't need the logs as "attributes", I am happy to remove it, please let me know.

I have added a couple of screenshots to show this working in Grafana. The first is the simple log output and the second screenshot shows the attributes being displayed as well.

Merge Requirements

For new features contributions, please make sure you have completed the following
essential items:

• [ *] CHANGELOG.md updated to document new feature additions
• Appropriate documentation updates in the docs
• Appropriate Helm chart updates in the helm-charts

Maintainers will not merge until the above have been completed. If you're unsure
which docs need to be changed ping the
@open-telemetry/demo-approvers.

[linux-foundation-easycla]

The committers listed above are authorized under a signed CLA.

• ✅ login: kerneljack / name: Khusro Jaleel (ebd2364, 3452c7d, fb55150, c1b11ff, 09dcfb4, 9ed4b4b)

[puckpuck]

@kerneljack can you resolve conflicts then rebuild the product-catalog service. There was some changes recently to the openfeature.SetProvider call which may need to be implemented when you resolve. See this commit for details.

[kerneljack]

@puckpuck I think I've fixed it. I've re-tested that the product catalog still works