This ensure clear separation of functionality. This PR does not change any functionality, it just restructures the code to separate global functionality from
the Default implementation. Also helps to ensure that Global initialization does not happen by mistake when working only with the default implementation.
Also it helps with methods like `OpenTelemetry.get()` and `OpenTelemetry.set()` to understand they are interacting with global instance
Signed-off-by: Bogdan Drutu <bogdandrutu@gmail.com>
Bogdan Drutu
Anuraag Agrawal