Brennan Taylor

Support more env vars for exporter configuration

4

It would be nice to configure things like `OTEL_EXPORTER_OTLP_HEADERS`, `OTEL_EXPORTER_OTLP_CERTIFICATE` and `OTEL_EXPORTER_OTLP_CLIENT_CERTIFICATE` like in the spec. https://opentelemetry.io/docs/concepts/sdk-configuration/general-sdk-configuration/ https://opentelemetry.io/docs/concepts/sdk-configuration/otlp-exporter-configuration/ https://github.com/open-telemetry/opentelemetry-specification/blob/main/specification/protocol/exporter.md