[CI]Added initial framework of CXX unittest (#98)

Based on the discussion in #53 , I just added the initial flow of CXX unittests for this repo, with providing two dummy UTs as placeholder to show the usage, feel free to add your own CXX unittests. 
@Superjomn  @ptillet 

@ptillet , in this PR, I also configure the integration-tests.yml to add the unittest into github CI check. 

Thanks

unittest/CMakeLists.txt

@@ -0,0 +1,27 @@
+
+include (${CMAKE_CURRENT_SOURCE_DIR}/googletest.cmake)
+
+include(GoogleTest)
+enable_testing()
+
+function(add_triton_ut)
+  set(options)
+  set(oneValueArgs NAME)
+  set(multiValueArgs SRCS LIBS)
+  cmake_parse_arguments(_ "${options}" "${oneValueArgs}" "${multiValueArgs}" ${ARGN})
+  add_test(NAME ${__NAME}
+          COMMAND ${__NAME})
+  add_executable(
+          ${__NAME}
+          ${__SRCS})
+  target_link_libraries(
+          ${__NAME}
+          GTest::gtest_main
+          gmock
+          ${__LIBS})
+
+  gtest_discover_tests(${__NAME})
+endfunction()
+
+add_subdirectory(Analysis)
+add_subdirectory(Conversion)