Update the user model to a single controller instead of multiple

Fixed all the bugs the new tests found

* Map type now set from General settings
* No map type control in maps

* Holds all the settings for the app
* Allows core plugin to override default values

Also added ui support for multiple complex item types

Prevent shutdown ordering crashes

Made QGCCorePlugin derive from QGCToolBox and expose everything through the same mechanism as everything else.