Add content and links to Azure OpenTelemetry

### Type of issue

Other (describe below)

### Description

Let's provide guidance and links to instrument, collect, and [analyze metrics on Azure app services](https://learn.microsoft.com/en-us/azure/azure-monitor/app/opentelemetry-enable?tabs=aspnetcore#enable-azure-monitor-opentelemetry-for-net-nodejs-python-and-java-applications).

cc @noahfalk @gewarren @BillWagner @tommcdon

### Page URL

https://learn.microsoft.com/en-us/dotnet/core/diagnostics/metrics-collection

### Content source URL

https://github.com/dotnet/docs/blob/main/docs/core/diagnostics/metrics-collection.md

### Document Version Independent Id

1cab703b-de5a-f0a2-bfa4-7c5df8d8423b

### Article author

@tommcdon

### Metadata

* ID: f111f896-9278-9ca4-a5eb-0a448a7be40d
* Service: **dotnet-fundamentals**