Move IDeviceFactory closer to IDevice implementation

Except for the DesktopDevice, which is kind of special. Also try
a bit to make (and partially fail at doing so) naming and code
structure (#include, use of namespaces) more similar to each other.

Change-Id: I9fe266e706b72c14f59ff03ca1ae02dba3adcc71
Reviewed-by: Christian Kandeler <christian.kandeler@qt.io>

src/plugins/android/androiddevice.h

@@ -26,6 +26,7 @@
 #pragma once
 
 #include <projectexplorer/devicesupport/idevice.h>
+#include <projectexplorer/devicesupport/idevicefactory.h>
 
 namespace Android {
 namespace Internal {
@@ -50,5 +51,12 @@ private:
     QUrl toolControlChannel(const ControlChannelHint &) const override;
 };
 
+class AndroidDeviceFactory : public ProjectExplorer::IDeviceFactory
+{
+    Q_OBJECT
+public:
+    AndroidDeviceFactory();
+};
+
 } // namespace Internal
 } // namespace Android