ProjectExplorer: De-QObject-ify BuildConfigurationFactories

The QObject was not heavily used. Object name was for debugging only,
translation context can be taken from the corresponding BuildConfiguration
objects, the qobject_casts in the three big importers are replaced by
dynamic_cast, which is good enough in that context.

Take the opportunity to re-use translations from base BuildConfiguration
for the common cases and sprinkle in some 'final'.

Change-Id: I8e9727c98c6e943cb333556861c24e701c2bdf45
Reviewed-by: Christian Kandeler <christian.kandeler@qt.io>

src/plugins/compilationdatabaseprojectmanager/compilationdatabaseproject.cpp

@@ -540,7 +540,7 @@ CompilationDatabaseBuildConfigurationFactory::CompilationDatabaseBuildConfigurat
     setSupportedProjectMimeTypeName(Constants::COMPILATIONDATABASEMIMETYPE);
 
     setBuildGenerator([this](const Kit *kit, const FilePath &projectPath, bool) {
-        const QString name = tr("Release");
+        const QString name = BuildConfiguration::tr("Release");
         ProjectExplorer::BuildInfo info(this);
         info.typeName = name;
         info.displayName = name;