Refacto pip installs CNR

[ShutdownRepo]

When installing deps through a venv, the ./venv/bin/python3 is not transparently made through CNR (Catch And Retry). Requires to prepend the command line with the CNR like: catch_and_retry ./venv/bin/python -m pip install deps ...

Would be better to do this:

cd /path/to/tool || exit
source ./venv/bin/activate
pip3 install -r ./requirements.txt
deactivate

pip2/pip3 are transparently handled through CNR.