Incorrect namespace issue

[cijothomas]

The following classes are in the root OpenTelemetry ns, as opposed to being in .Trace or .Logs namespace. Given this was not identified before 1.0.0 stable, changing this now would be breaking change. This issue is opened for tracking fixing this when we do a major bump.

https://github.com/open-telemetry/opentelemetry-dotnet/blob/main/src/OpenTelemetry/SimpleActivityExportProcessor.cs#L19
https://github.com/open-telemetry/opentelemetry-dotnet/blob/main/src/OpenTelemetry/BatchActivityExportProcessor.cs#L19
https://github.com/open-telemetry/opentelemetry-dotnet/blob/main/src/OpenTelemetry/SimpleLogRecordExportProcessor.cs#L19
https://github.com/open-telemetry/opentelemetry-dotnet/blob/main/src/OpenTelemetry/BatchLogRecordExportProcessor.cs#L19