Update naming convention for event.state

Currently we are split between:

"events":

• events.facade

"event":

• event.action
• event.effect
• event.state
• event.selector
• IEventState

It would be nice to be more consistent, and maybe a bit more accurate. For instance, it feels weird to have IEventState with "events" as part of event state. I would like to rename this to "feed", "earthquakes", "data", "catalog" so that some of our actions and state read a bit more logically. We would have "feed.events" and "feed.isLoading" or "feed.lastUpdated".