Move all persisted state out of AppManager to where it really
belongs. To do that, inject a shared KeyValueStore object into
managers that need to persist part of their state in a strongly
typed manner.
Below are persisted states:
- PersistenceManager
- persistenceAuthor
- ProfileManager
- activeProfileId
- UpgradeManager (formerly AppManager)
- didMigrateToV2 (migrate former value)
- VPNManager
- tunnelLogFormat
- masksPrivateData
A similar approach is used for app-specific preferences, by using
a strongly typed enum (AppPreference) together with SwiftUI
@AppStorage property wrapper.
Worth moving logging logic into a specific LogManager.
Finally, drop any former view dependency on AppManager, as states
are now accessed through specific managers.