Review and enhance logging support for cart service (C#)

[cartersocha]

As OpenTelemetry Logging has not fully stabilized, this list of requirements may change in future releases.

• Log events in existing services should be converted to span events where appropriate (i.e., the event occurs within a transaction)
• Logs should be emitted with OpenTelemetry resources and context for correlation where possible.
• Logs should be scraped by OpenTelemetry Collectors for further filtering and processing.

Referencing issue: #44

Service: Service: https://github.com/open-telemetry/opentelemetry-demo-webstore/tree/main/src/cartservice

[cijothomas]

I can help with this item.
To begin with, I can replace the Console.Write with ILogger calls.,
Then wire up OpenTelemetry with OTLP Exporter.
Then add resources.

Not sure about using SpanEvent vs using dedicated Logging API. Do we have a preference on one vs other?

[cartersocha]

From the architecture doc I think our preference is to set this as a span event.

"Services should attach log events to spans where appropriate
E.g., the log occurs during a span transaction"

@austinlparker or @jsirianni feel free to correct me!

[austinlparker]

Closing this as logs are being pushed out