Load OTel SDK config from environment variables and system properties.…#1434

trask merged 12 commits intoopen-telemetry:mainopen-telemetry/opentelemetry-java-contrib:mainfrom

cyrille-leclerc:source-otel-sdk-confi-from-system-out-and-envcyrille-leclerc/opentelemetry-java-contrib:source-otel-sdk-confi-from-system-out-and-envCopy head branch name to clipboard