Revise the use of reflection

Right now, there are places where reflection is used even if it's not necessary. Weld SE and Servlet did originally depend on the Weld API. That's no longer the case - they both depend on the weld-core quite for a long time.

We also have three different reflection util classes:

• org.jboss.weld.util.reflection.Reflections
• org.jboss.weld.environment.util.Reflections
• org.jboss.weld.environment.servlet.util.Reflections

Ideally, there should be only one util class or one for weld-core and one for weld-environment-common.