* Add a JUnit5 extension for setting up OpenTelemetry in a test.
* git add
* Split API and management accessors.
* Update sdk/testing/src/main/java/io/opentelemetry/sdk/testing/junit5/OpenTelemetryExtension.java
Co-authored-by: Giovanni Liva <giovanni.liva@dynatrace.com>
Co-authored-by: Giovanni Liva <giovanni.liva@dynatrace.com>