Move remaining instrumentation libraries to the opentelemetry-dotnet-contrib repo

[vishweshbankwar]

The repo currently maintains the following instrumentation libraries:

• OpenTelemetry.instrumentation.AspNetCore
• OpenTelemetry.instrumentation.HttpClient
• OpenTelemetry.instrumentation.SqlClient
• OpenTelemetry.instrumentation.GrpcNetClient

We should consider them moving all to the contrib repo and keep this repo focused mainly on core components.

[cijothomas]

We'll miss some extra test coverage by doing this, but that is okay, since all signals/instrumentations are stable already!

[vishweshbankwar]

@cijothomas - Thats a good point. I think that can be managed by upgrading the dependencies on instrumentation libraries in timely manner.

[Kielek]

Labels on contrib side:

• https://github.com/open-telemetry/opentelemetry-dotnet-contrib/labels/comp%3Ainstrumentation.grpcnetclient
• https://github.com/open-telemetry/opentelemetry-dotnet-contrib/labels/comp%3Ainstrumentation.sqlclient
• https://github.com/open-telemetry/opentelemetry-dotnet-contrib/labels/comp%3Ainstrumentation.httpclient
• https://github.com/open-telemetry/opentelemetry-dotnet-contrib/labels/comp%3Ainstrumentation.aspnetcore

[reyang]

Also, migrate the existing GitHub issues that are related to these components.

[reyang]

I think this is done.