[Otel Trace API] Create a test app to generate OTel Span Links

[jasonjkeller]

We will need a test app that exercises the Span Links functionality. Ideally, this demo app can be extended: https://github.com/jasonjkeller/opentelemetry-api-bridge

[Newrelic-Boomi]

https://new-relic.atlassian.net/browse/NR-488885