[AzureMonitorLiveMetrics] POC

[TimothyMothra]

This PR commits a working Proof of Concept. This is the first working POC that gets data into the Azure Portal.
THIS IS NOT FINAL. After committing these changes, I will merge my POC with Raj's and work on additional enhancements.

Changes

• Demo project
  • updated Program.cs to generate telemetry in a loop. This is needed to generate traffic to see LiveMetrics in the Azure Portal.
• LiveMetrics project
  • Added a Customization of QuickPulseSDKClientAPIsRestClient.cs. This is needed because the Generated RestClient has a deserialization bug.
  • Added ManagerFactory, Manager, and Manager.Metrics.
    This is modeled off of the Transmitter class in our AzureMonitorExporter. The Factory ensures that we only have one instance of the Manager per ConnectionString. The Manager class has the HTTP traffic (Ping & Post). The Manager.Metrics handles our metrics.
  • Added LiveMetricsMetricExporter to translate OTel Metrics to AzureMonitor Metrics
  • Added LiveMetricsTraceExporter as the entry point to my POC and is used to initialize the Manager class.

Future Work

• My Exporters will be merged with Raj's
• Consolidate Constants.
• Replace OTel Metrics SDK with custom implementation for lower overhead.

[TimothyMothra]

This is needed to read Performance Counters (CPU & Memory) to enable POC. Will work on removing this in the future.

[rajkumar-rangaraj]

We may need to keep this one forever, there is no good way to get this value.

[TimothyMothra]

I'm fine with this dependency, as System.Diagnostic is a core dependency of OTel.
Application Insights is able to read perf counters without an extra dependency. I need more time to investigate how that works. For short term, this is fine. :)

[rajkumar-rangaraj]

AI SDK uses System.Diagnostics.PerformanceCounter - https://github.com/microsoft/ApplicationInsights-dotnet/blob/de66d679ff32f5a74553edbf52b10b9dc57ded70/WEB/Src/PerformanceCollector/PerformanceCollector/Perf.csproj#L32

[azure-sdk]

API change check

APIView has identified API level changes in this PR and created following API reviews.

Azure.Monitor.OpenTelemetry.LiveMetrics

[rajkumar-rangaraj]

Approving as POC. This requires a complete clean up later.