* SDK/Components/Python - Removed python_op in favor of python_component
* Added test for python_component + func_to_container_op.
* dsl.PythonComponent class is removed, because the metadata is now properly stored in the function object itself.
* build_python_component now optionally accepts base_image and no longer requires the decorator (but can use decorator's metadata).
* Made staging_gcs_path optional since it's only needed when build_image == True
* Added more validation
* Added description and parameter help to python_component
* Fixed the pipeline path string after merge.
* Addressed the PR comments.
Added more detailed explanation of base_image selection to the docstring.
* Removed extra empty lines
* Switching to map-based syntax for the arguments.
The list-based syntax is going to be deprecated.
* Switched to map-style arguments in _func_to_component_spec
* Updated testdata
Alexey Volkov
Alexey Volkov
Pascal Vicaire