QmakeAndroidSupport: Move AndroidPackageInstallationStep to Android plugin

There's nothing Qmake related in there (anymore?).

Change-Id: I8842d4824065cf3cba61d50b6f333ec3b52e3851
Reviewed-by: Vikas Pachdha <vikas.pachdha@qt.io>

src/plugins/android/android.pro

@@ -53,7 +53,8 @@ HEADERS += \
     adbcommandswidget.h \
     androidsdkpackage.h \
     androidsdkmodel.h \
-    androidsdkmanagerwidget.h
+    androidsdkmanagerwidget.h \
+    androidpackageinstallationstep.h
 
 SOURCES += \
     androidconfigurations.cpp \
@@ -100,7 +101,8 @@ SOURCES += \
     adbcommandswidget.cpp \
     androidsdkpackage.cpp \
     androidsdkmodel.cpp \
-    androidsdkmanagerwidget.cpp
+    androidsdkmanagerwidget.cpp \
+    androidpackageinstallationstep.cpp
 
 FORMS += \
     androidsettingswidget.ui \