Status Reporting and Improvements

This MR revises the way that state is reported in the UI following further suggestions by Jamie Gravendeel. Namely, the UI for the Syncing state is now clearer and better suited for long-running operations; The current tradeoff is that it's effectively not readable for short operations. (I.e. Syncing without any change)

The MR also adds a new Notification that is only sent when the user manually syncs to let them know when the process is complete. This required refactoring the sync_now() method.

Lastly, we now also inhibit session changes while Syncing(_) is in process, preventing the user from accidentally killing the daemon.

There are three open questions:

• We might want to mitigate the new UI from being short lived in some way but I'm not sure it would be necessary; Perhaps we could keep track of how long Syncing(_) has been going on for and, if above a certain amount of time, we could switch to the new view but that also wouldn't leave us with the certainty it can be seen for long enough as we cannot predict the time Syncing will take.
• Do we want to inhibit all session changes as the MR currently does?
• The Strings have not been revised by #design yet and the new UI is based off discussions alone, not a mock-up so any feedback is appreciated

Closes: #48 (closed)