Weld 5 - change the default behavior of empty beans.xml

Among changes for next CDI version, there is also a change to behavior of empty beans.xml which should switch from mode all} to {{annotated.
On top, we need to make sure there is a config switch (at least for EE env) to bring back previous behavior as that will be a spec requirement.

See https://github.com/eclipse-ee4j/cdi/issues/500

ATM this is not captured in CDI or in TCK so there are no tests for it.

Along with introducing this change, the config and our own tests, I suspect we might need to change a bunch of existing tests to make sure they keep passing.