Added a done button which closes the settings UI.
Displays a warning before the user logs out of the last saved account. If they proceed with the logout, they will be redirected to the login UI.
Added startup handling for when the user has 0 saved accounts. They will be brought directly to the login UI.
Accounts are now validated each time they are switched.
Features:
* Add a new account.
* Switch accounts.
* Log out of an account.
Also added a cancel button to the login UI which is only shown when a user is adding an account. In that case, the operation should be and is cancellable.
Added a tooltip to the settings button on the landing UI.
Settings button now opens to the (incomplete) settings UI.
Added navigation bar to the settings UI.
Implemented tabbing between settings tabs.
More to come.
