Update SDK Observability docs to include instructions and samples for the **Azure.Monitor.OpenTelemetry.AspNetCore** package

[argium]

Please update the SDK Observability page to include instructions and code samples for the Azure.Monitor.OpenTelemetry.AspNetCore package.

Details
Application Insights documentation recommends that new applications use Azure Monitor OpenTelemetry for .NET (aka. Azure.Monitor.OpenTelemetry.AspNetCore) instead of their classic APIs for instrumentation. The CosmosDB SDK Observability documentation provides instructions and code samples for Azure.Monitor.OpenTelemetry.Exporter and Microsoft.ApplicationInsights.AspNetCore, but not the recommended one.

OpenTelemetry is relatively new for me so I'm not sure how to configure it. My solution does not use ActivitySource, and none of the code samples are compatible with the App Insights documentation.

var otel = services
    .AddOpenTelemetry()
    .ConfigureResource(r => r.AddService(environment.ApplicationName))
    .UseAzureMonitor();

services.Configure<OpenTelemetryLoggerOptions>((loggingOptions) =>
{
    loggingOptions.IncludeScopes = true;
});

As a result, CosmosDB requests do not show up correctly in the App Insights Azure portal UI out of the box. Azure Storage SDK works as expected.