add CFDP fault handler mock

unittests/cfdp/pdu/CMakeLists.txt

@@ -0,0 +1,13 @@
+target_sources(
+  ${FSFW_TEST_TGT}
+  PRIVATE testAckPdu.cpp
+          testAckPdu.cpp
+          testEofPdu.cpp
+          testNakPdu.cpp
+          testFinishedPdu.cpp
+          testPromptPdu.cpp
+          testKeepAlivePdu.cpp
+          testMetadataPdu.cpp
+          testFileData.cpp
+          testCfdpHeader.cpp
+          testFileDirective.cpp)