QmlProject: Add support for setting the environment

This allows setting arbitrary environment variables
in the .qmlproject.
This is required for example qtquickcontrols2.conf
and QT_AUTO_SCREEN_SCALE_FACTOR.

Task-number: QTCREATORBUG-19513
Change-Id: I8421a9fc7f85d24b3564f1b60f383be3838f2af4
Reviewed-by: Alessandro Portale <alessandro.portale@qt.io>

src/plugins/qmlprojectmanager/fileformat/qmlprojectitem.cpp

@@ -106,4 +106,14 @@ bool QmlProjectItem::matchesFile(const QString &filePath) const
     return false;
 }
 
+QList<Utils::EnvironmentItem> QmlProjectItem::environment() const
+{
+    return m_environment;
+}
+
+void QmlProjectItem::addToEnviroment(const QString &key, const QString &value)
+{
+    m_environment.append(Utils::EnvironmentItem(key, value));
+}
+
 } // namespace QmlProjectManager