added all checks, made checker func generic

mission/system/tree/util.cpp

@@ -0,0 +1,9 @@
+#include "util.h"
+
+#include "fsfw/serviceinterface.h"
+
+void subsystem::checkInsert(ReturnValue_t result, const char* ctx) {
+  if (result != HasReturnvaluesIF::RETURN_OK) {
+    sif::warning << "satsystem::checkInsert: Insertion failed at " << ctx << std::endl;
+  }
+}