Feature: Replace 'online' user list with recent updates

[jschuur]

Move away from the concept of being 'online' or 'away', to avoid complications of reliably tracking a user's presence, when they may not have the tab open or it might not be visible.

Instead, replace 'online' with a list of everyone who did any status update (text or drop down) in the last 24 hours, sorted by the time ('Recently'?).

'Away' could then become a separate segment ('Focused'?) for anyone who did a drop down status option change between, say 4/6 and 24 hours ago.

Users that are online get a green dot on their avatar again.

• [ ] show most recent update within window of time, chronologically sorted, regardless of online status
• [ ] initially load from database
• [ ] keep local copy on PK server up to date
• [ ] toggle to enable grouping by online status (default) (would address #123)
• [ ] drop down to change recency window (3, 6, 12, 24 hours, 2, 3 5 days?)

[jschuur]

Initial work done in ae41945910b0bbf813ac2cf5fc5586fb62a7df8e to refactor when the status update state is updated on reconnects and introduce updated away avatar UI.