Add mypy and add typechecking step to script/test

Only check atst/domain/csp/cloud.py for now

script/include/run_test

@@ -35,6 +35,9 @@ if [ "${RUN_PYTHON_TESTS}" = "true" ]; then
   output_divider "Perform static analysis on Python files"
   run_python_static_analysis "${PYTHON_FILES}"
   ((python_test_status+=$?))
+  output_divider "Perform type checking on Python files"
+  run_python_typecheck
+  ((python_test_status+=$?))
   output_divider "Run Python unit test suite"
   run_python_unit_tests "${PYTHON_FILES}"
   ((python_test_status+=$?))