feat(opentelemetry-config): set headers from headers_list#6060

JamieDanielson wants to merge 4 commits intoopen-telemetry:mainopen-telemetry/opentelemetry-js:mainfrom

JamieDanielson:jamie.config-headers-listJamieDanielson/opentelemetry-js:jamie.config-headers-listCopy head branch name to clipboard