Azure.Sdk.Tools.NotificationConfiguration_1.0.0-dev.20211018.1

Updates to Identity Resolver (#2085)

* Fix up identity resolver to make it more reliable, publish notification configuration as a tool

* Combine CodeOwners parser tools into a single library

* Switch codeownersparser to netstandard2.0

* Add dotnet tool for retrieving codeowners info

* Add tool for retrieving codeowners

* Use both username and email to resolve queuing user

* Specify dotnet sdk version