Lite/Full split: decide on "The `EventMetadata` interface"

[Ladicek]

The "The EventMetadata interface" chapter has a TODO for deciding whether we should mention BeanManager.getEvent() or BeanContainer.getEvent().

https://github.com/eclipse-ee4j/cdi/blob/864e1b4f779e4d6d5a80f147d975a510446d4987/spec/src/main/asciidoc/core/events.asciidoc

[manovotn]

Since getEvent() is now on BeanContainer, we should mention that one instead.