refs https://github.com/TryGhost/Team/issues/1277
- moved event parsing from a component to a helper
- keeps code as a plain function
- allows for per-event parsing which helps with rendering as we're not rebuilding/re-rendering a whole array each time the events data changes when a new page is loaded
- updated to include full member and email objects (will be used later for email preview popup)
- updated members-activity table row component to use the event parser helper for better event details
refs https://github.com/TryGhost/Team/issues/1277
- re-uses same fetcher resource used on member activities screen
- allows for component to be simplified as it no longer needs to care about handling data loading itself
- drops use of 1-minute data caching as there is no real need for it in typical usage and can be confusing when the dashboard didn't update as expected
- exposed error message on `members-event-fetcher` if one is encountered
refs https://github.com/TryGhost/Team/issues/1277
- renamed `<GhActivityTimeline>` to `<GhMemberActivityEventParser>` and modified so that it yields parsed events rather than directly renders them
- makes the component re-usable as it can be used to decorate raw events ready for use in context-specific templates
- switches to using a getter to yield the parsed events so that they will update automatically when the `@events` argument changes
- updated `<Dashboard::LatestMemberActivity>` to use `<GhMemberActivityEventParser>` and keep the member activity box output local to itself
- added integration tests for `<Dashboard::LatestMemberActivity>`
- added Mirage setup for member activity event models/serializers/route
refs https://github.com/TryGhost/Team/issues/1277
- first step of further refactoring to make member activity display more generic
- separates component data loading from overall controller logic and allows it to be tested in integration tests as well as acceptance tests
