…, yet support testing

Refactored existing global instances to use it

EnumMapperProvider as a proper service
Support for existing instance descriptor, to be able to register custom instances during tests (even for types that do not have a service descriptor) + fixed appropriate code in registry, which used Set instead of List
Fixed typo in registry module info

… will work nicely once Helidon Service Inject is introduced

- sets up registry with appropriate configuration (through annotations, test source, or static methods)
- resets global instances when test class is done

…nces (ClassToInstanceStore)

This also binds the current context to the test class that is executed, making parallel testing a possibility.

…otations.

… all tests

…entation.

Also removed the no-op, as it is no longer needed

Using a more specific classifier.

…stry.java

Co-authored-by: Daniel Kec <[email protected]>