Make the population asynchronous on dbus. Wait for the device list and
don't populate it until it's ready. There's no reason to block.
Don't emit after endInsertRows. It doesn't help, as the views will have
already refreshed.
Benefits:
- We had config files in different paths, now they will be centralized.
- Daemon, LanLinkProvider and NetworkPackage depend only on Qt now.
- KConfig is accessed with strings as keys, where a typo can go unnoticed.
- Daemon is now thinner, as it doesn't need to initialize config values.
- QCA::Initializer is in a single place now (was in Daemon and Plugin).
