Android: Add Android tool manager

Refactor the use of android tool and groundwork for the new sdk
and avd management tool's integration

Task-number: QTCREATORBUG-17814
Change-Id: I6a5920f9ba92508f904cd8cf28bf62c82de2d820
Reviewed-by: BogDan Vatra <bogdan@kdab.com>

src/plugins/android/androidmanager.h

@@ -89,6 +89,7 @@ public:
     static AndroidQtSupport *androidQtSupport(ProjectExplorer::Target *target);
     static bool useGradle(ProjectExplorer::Target *target);
     static bool updateGradleProperties(ProjectExplorer::Target *target);
+    static int findApiLevel(const Utils::FileName &platformPath);
 };
 
 } // namespace Android