Wizards: allows filtering of wizards based on Qt version

Every wizard now implements requiredFeatures() to define a feature set.
If the feature set is not satisfied by the available Qt Versions,
the wizard is not shown in the create file/project dialog.

Every Qt version can define the provided feature set in availableFeatures()
defined in BaseQtVersion.

Change-Id: Ie9e2c210d19187b2296451948c36d274f2096623
Reviewed-by: Daniel Teske <daniel.teske@nokia.com>
Reviewed-by: Alessandro Portale <alessandro.portale@nokia.com>

src/plugins/designer/cpp/formclasswizard.h

@@ -55,6 +55,8 @@ public:
     QString sourceSuffix() const;
     QString formSuffix() const;
 
+    virtual Core::FeatureSet requiredFeatures() const;
+
 protected:
     virtual QWizard *createWizardDialog(QWidget *parent,
                                         const QString &defaultPath,