clean up code structure a bit

mission/system/acs/StrFdir.cpp

@@ -0,0 +1,14 @@
+#include "StrFdir.h"
+
+#include "mission/acs/defs.h"
+
+StrFdir::StrFdir(object_id_t strObject)
+    : DeviceHandlerFailureIsolation(strObject, objects::NO_OBJECT) {}
+
+ReturnValue_t StrFdir::eventReceived(EventMessage* event) {
+  if (event->getEvent() == acs::MEKF_INVALID_MODE_VIOLATION) {
+    setFaulty(event->getEvent());
+    return returnvalue::OK;
+  }
+  return DeviceHandlerFailureIsolation::eventReceived(event);
+}