docker: Change Settings to single owner

We change DockerSettings to have a single owner.
Since DockerDevices are destroyed after the plugin
is unloaded, we have to make sure to remove the
settings from devices during plugin teardown.

For this we store a list of created devices in
the factory, and call their shutdown function when
the plugin unloads.

Change-Id: Ic9c7d8ad9437c48d68f20c9a8f8ad7449b3cb972
Reviewed-by: hjk <hjk@qt.io>

src/plugins/docker/dockerapi.h

@@ -42,7 +42,7 @@ class DockerApi : public QObject
     Q_OBJECT
 
 public:
-    DockerApi(QSharedPointer<DockerSettings> settings);
+    DockerApi(DockerSettings *settings);
 
     static DockerApi *instance();
 
@@ -63,7 +63,7 @@ private:
 private:
     Utils::optional<bool> m_dockerDaemonAvailable;
     QMutex m_daemonCheckGuard;
-    QSharedPointer<DockerSettings> m_settings;
+    DockerSettings *m_settings;
 };
 
 } // namespace Internal