Initial Release

This is the initial release of the opentelemetry instrumentation, designed to work with https://github.com/wyhaines/opentelemetry-api.cr to make it easy to instrument your Crystal apps with OpenTelemetry.

The autoinstrumentation should only install if the packages that it is supposed to instrument are installed, at the required versions.

Further testing is needed, but earlier tests seemed to work as expected with New Relic.