Provide extension on the HTTP client to propagate dependency ID (option #2)

[stijnmoreels]

Is your feature request related to a problem? Please describe.
When sending out a HTTP message, we need to track it as a HTTP dependency in Application Insights. To link the correlation between services, we need to propagate the dependency ID to the HTTP telemetry model and enrich the HTTP headers with the correlation information.

Describe the solution you'd like
Option 2 is to create an extension on the HttpClient that takes in:

• the operation name, and
• the correlation information

Describe alternatives you've considered
Option 1: where we provide a dedicated HTTP message handler #257.

Additional context
https://thomaslevesque.com/2016/12/08/fun-with-the-httpclient-pipeline/
https://github.com/arcus-azure/arcus-service-to-service-correlation-poc
https://docs.microsoft.com/en-us/aspnet/core/fundamentals/http-requests?view=aspnetcore-5.0