Add generic status flag methods
Replace firstLaunch flag methods with new generic method

Also update names of generic methods, and use `remove()` in
`StatusManager.clear()`
Move method down in file
Replace resultsNotifiedDashboard with generic flag methods
Convert resultsNotified to generic flag methods
Convert notificationExpiryExplained to generic flag methods
Convert parametersFlushed to generic flag methods
Merge pull request #402 from daydreaming-experiment/feature/factorize-status-flags

Factorize status flags