Investigate py3-virtualenv and python3 -m venv, and python install --user in HelixPrecommands

With the iOS Startup work, I found issues installing py3-virtualenv with the default HelixPrecommands. In the Mac Case for iOS, venv is included with newer versions of python by default. This is likely the case for other OSes but have not tried it yet. I also had to remove the --user as it was causing errors and then not installing the storage module. (Related https://stackoverflow.com/questions/30604952/pip-default-behavior-conflicts-with-virtualenv)