python install script should finish the migration to uv

[eisenefaust]

data/r-session-complete/scripts/install-python.sh
uses pip to install packages.

this should use uv instead of pip to follow the initial migration to uv that was performed.

At a minimum, setting
export UV_HTTP_TIMEOUT=60
export UV_INDEX_URL="https://packagemanager.posit.co/pypi/latest/simple"

or better, using a uv.toml to set system wide configuration settings:
something like in /etc/uv/uv.toml
[[index]]
url = "https://packagemanager.posit.co/pypi/latest/simple"

and
uv pip install --python /opt/python/${PYTHON_VERSION}/bin/python
--break-system-packages
ipykernel
jupyter
...