* Add isort_code.sh to sanity tests
* Run tools/distrib/isort_code.sh
* Fine tune the import order for relative imports
* Make pylint and project generation happy
* Fix a few corner cases
* Use --check instead of --diff
* The import order impacts test result somehow
* Make isort print diff and check output at the same time
* Let tools/run_tests/python_utils be firstparty library
* Run isort against latest HEAD
* Add grpcio-csds pacakge
* Remove unused file
* Fix the proto import path issue
* Update the CSDS package and xds-protos for PY2
* Make tests happy
* Fix Bazel proto dependency
* Add Python2 tests for CSDS