WELD-1715, WELD-1714, WELD-1658 Extensive refactoring of weld-se and weld-servlet

- extract common logic into a new module
- unify the deployment and bean discovery process

Weld Servlet
- bean-discovery-mode="annotated" support and isolated bean archives
- add support for WEB-INF/classes/META-INF/beans.xml location
- adapt discovery/isolation tests from Weld SE
- drop outdated/deprecated stuff (TomcatListener, VFSURLScanner, etc.)