We don't need test-ubuntu-py-ver.yml since we can use "include". Test
Python 3.14t as well. More Python versions can be tested now we are
using setup-python.
Update scripts to use actions/setup-python to install different Python
versions. Add run-faber.sh and get-py-env.py scripts. Add
test-ubuntu-py-ver.yml CI script to test with different Python versions.