Since we added support for Python 3.12, our tests have been taking
longer to complete and we've been seeing an increase in timeout errors.
We already increased timeout in #34550, this PR increase timeout for
release and pull_request jobs.
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* add release version of grpc_distribtests_* jobs .cfg files
* make grpc_distribtests_ruby more aligned with other single-job distribtests
* dont hide packages from build_artifacts step for python an php
The source code is moved from src/python to
src/python/src. A setup.py is added at
src/python. The build_python.sh and
run_python.sh scripts are updated to build
and run the Python tests by building a
package and installing it in the developer's
Python 2.7 virtual environment.