Gaps in kestrel version of networking test echo server (as compared to obsolete CoreFxNetCloudService)

In https://github.com/dotnet/runtime/pull/52642 as part of https://github.com/dotnet/runtime/issues/42852 we are bringing kestrel version of the obsolete CoreFxNetCloudService echo test server.

The proposed implementation is missing:

• Any deployment logic to be able to host it in Azure
• Any test certificates, which the unit tests may expect
• ClientCertificate capturing in NetCoreServer\Helpers\RequestInformation.cs and necessary setup of kestrel to receive it.
  • See this conversation
  • it probably makes this test always pass the null asssert.
• delete the obsolete CoreFxNetCloudService from runtime repo