Metric instrumentation for SQLClient

[cijothomas]

Similar to: https://github.com/open-telemetry/opentelemetry-dotnet/blob/main/src/OpenTelemetry.Instrumentation.AspNetCore/Implementation/HttpInMetricsListener.cs

No semantic conventions exist as of today for db, but can still do a basic sql call duration metric. The instrumentations are not stable release anyway, so we can make changes as spec evolves. The goal is to get some metrics flowing automatically for libraries which already have traces enabled.

[cijothomas]

https://github.com/open-telemetry/opentelemetry-specification/pull/2070/files

[pantosha]

https://github.com/open-telemetry/opentelemetry-specification/pull/2070/files

@cijothomas are you going to merge this PR?

[cijothomas]

https://github.com/open-telemetry/opentelemetry-specification/pull/2070/files

@cijothomas are you going to merge this PR?

I am not.

[pantosha]

Oh, sorry, I missed that this is a link to a pull request with a convention.
Thank you for the fast answer 😊