Add copyrights to Python code

src/python/src/__init__.py

src/python/src/_adapter/__init__.py

.../src/_adapter/_blocking_invocation_inline_service_test.py

src/python/src/_framework/__init__.py

src/python/src/_framework/base/__init__.py

src/python/src/_framework/base/packets/__init__.py

src/python/src/_framework/common/__init__.py

src/python/src/_framework/face/__init__.py

src/python/src/_framework/face/testing/__init__.py

src/python/src/_framework/foundation/__init__.py

src/python/src/_junkdrawer/__init__.py

test/core/end2end/gen_build_json.py

tools/buildgen/build-cleaner.py

tools/buildgen/bunch.py

tools/buildgen/mako_renderer.py

tools/buildgen/plugins/expand_filegroups.py

tools/buildgen/plugins/generate_vsprojects.py

tools/buildgen/plugins/list_protos.py

tools/distrib/check_copyright.py

tools/run_tests/jobset.py