[OTLP Exporter] Use env for endpoint, timeout#451

jtescher merged 2 commits intoopen-telemetry:mainopen-telemetry/opentelemetry-rust:mainfrom

ozerovandrei:168-otlp-span-exporter-env-cfgozerovandrei/opentelemetry-rust:168-otlp-span-exporter-env-cfgCopy head branch name to clipboard