Design distinct states for "Disconnected" and "Deactivated"

As mentioned in tpo/applications/vpn#255 (closed), we should split the current "Disconnected" state into two statuses:

1. Disconnected (red): Occurs in the event the VPN is disconnected due to an error, and should include a dialog or similar component with additional information about the issue.
2. Deactivated (yellow): Final name TBD, but could also be some variation of "Stopped" or "VPN Off" (will need to do a little research into what other VPNs call this state first).