Summary:
The TaskQueue does it's own throttling and has it's own processQueue retry timeout, no need for longPollConnected
Remove dead code (OfflineError)
Rename long connection state to status so we don't ask for `state.state`
Remove long poll actions related to online/offline in favor of exposing connection state through NylasSyncStatusStore
Consoliate notifications and account-error-heaer into a single package and organize files into sidebar vs. header.
Update the DeveloperBarStore to query the sync status store for long poll statuses
Test Plan: All existing tests pass
Reviewers: juan, evan
Reviewed By: evan
Differential Revision: https://phab.nylas.com/D2835
