Override Service Name

[blakeromano]

We have a use case where we'd like to overwrite the default service.name from the deployment name into a enviornment variable we push into the pod.

I am not sure what the disadvantage would be in terms of adding that ability.

I'd also be okay with an annotation to edit it. Could add an additional if statement here. https://github.com/open-telemetry/opentelemetry-operator/blob/main/pkg/instrumentation/sdk.go#L210-L227

[blakeromano]

https://github.com/open-telemetry/opentelemetry-operator/pull/939