* remove unused imports
* use google as isort profile
* sort imports
* format with yapf
* clean end of file new line, trailing whitespace, double quoted strings
* Reformat sdk only using the new yapf config.
* Reformat docstrings using docformatter.
* update golden files to resolve diff caused by whitespaces
* fix some tests
* format .py files under sdk/python/tests using yapf
* additional docformatter
* fix some tests
* feat(sdk/dsl/compiler): support --mode flag which can turn on v2 compatible mode
* override compiler default mode using KF_PIPELINES_COMPILER_MODE env var
* update V1_LEGACY to V1
* add unit tests
* address feedback
* clean up
* cleanup again
* use absl.testing.parameterized for table driven tests
* update