Move the onboarding/login state machine to the top level in main.qml, so that logout events can trigger new states.
Add Loader to statemachine so that each component is lazy-loaded. Initial tests saved 50MB of memory on startup.
Currently, logging out, then logging back in to the same or different account results in a doubling-up of chats/messages/wallet accounts. These need to be reset, however I need help doing that and it would delayed and blown out this PR further. This reset has been done for Onboarding and Login, but needs to be done for chats, wallet, mailservers, etc.