fix(build): Add header <optional> for gcc-11 compatiblity

Include files of gcc-11 do not recursivly include or declare
the std::optional header, making explicit inclusion in some files
neccessary.
Signed-off-by: Rene Paris <rene.paris@in-tech.com>

sim/src/common/spawnPointLibraryDefinitions.h

@@ -13,6 +13,7 @@
 #include <string>
 #include <memory>
 #include <vector>
+#include <optional>
 
 class ParameterInterface;
 class ScenarioInterface;

sim/src/common/xmlParser.h

@@ -19,6 +19,7 @@
 #include <optional>
 #include <string>
 #include <unordered_map>
+#include <optional>
 
 #include <QDomDocument>
 #include <QFile>