AutoTest: Add a itestframework.cpp

To get a few things out-of-line in itestframework.h.

Change-Id: Iae6f702b789c98b17a4d255008736377030e3b6c
Reviewed-by: Christian Stenger <christian.stenger@qt.io>

src/plugins/autotest/testframeworkmanager.cpp

@@ -91,10 +91,4 @@ void TestFrameworkManager::synchronizeSettings(QSettings *s)
     }
 }
 
-Id ITestFramework::settingsId() const
-{
-    return Core::Id(Constants::SETTINGSPAGE_PREFIX)
-            .withSuffix(QString("%1.%2").arg(priority()).arg(QLatin1String(name())));
-}
-
 } // namespace Autotest