Change visibility of scopes implementations

This request is linked to this PR in quarkiverse/quarkus-jberet extension.

Quarkus use its own implementation for scopes.
In linked PR, Quarkus implementations delegate to JBeret scopes implementations to do the work, but due to reduced visibility of JBeret scopes use of reflection is necessary, but should be avoided.

Currently XXXScopedContextImpl constructor and relative getXXXScopedBeans are the only methods accessed from quarkus-jberet extension; found a way to make them accessible without reflection.