Rename `OpenTelemetry.Exporter.Stackdriver` to align with the Google Cloud product name

[Rishabh-V]

Issue with OpenTelemetry.Exporter.Stackdriver

The current name of exporter is Stackdriver. However, this name is no longer used by Google Cloud. This creates a discoverability issue for new developers who are unaware of the old name Stackdriver.

Since the package is still prerelease, it would be beneficial to rename the exporter to OpenTelemetry.Exporter.GoogleCloudTrace or similar . This change would make the exporter more easily discoverable and align its name with the Google Cloud product naming.

We can keep the reference of Stackdriver in the documentation, so that current users of exporter know that the same has been renamed.

I had raised this as a question in #1167. And based on this suggestion from @Kielek, I am raising a dedicated issue.

[Rishabh-V]

@SergeyKanzhelev: Your thoughts please.

[Rishabh-V]

Ping on this one. @SergeyKanzhelev

I am happy to contribute and raise a PR if we are fine renaming this. Please let me know. Thanks.

[punya]

I agree with the name OpenTelemetry.Exporter.GoogleCloudTrace.

[SergeyKanzhelev]

One thing to decide before the rename is whether we want to combine different signal exporting into a single NuGet or have NuGet per signal (logging, metrics).

@punya wdyt the name can be if we combine signals together?

[punya]

In the OTel Collector, we use the name googlecloudexporter for the combination of all signals. I'd be okay with using that pattern here as well (though we might not need to actually implement metrics/logs depending on users' actual needs). I.e., it could be OpenTelemetry.Exporter.GoogleCloud.