* Extension packages should not use "internal" API package
Add InternalApiProtectionTest which uses ArchUnit to enforce architectural constraints.
This change only verifies that classes in `extensions` packages do not use classes in `internal` package of API module.
Test was added into `opentelemetry-all` module because the latter depends on all other submodules
and therefore sees all classes in the project.
* Polish
* Polish
David Poncelow
Carlos Alberto Cortez
Nikita Salnikov-Tarnovski
Bogdan Drutu