ooni: create virtualenv bootstrap script that allows us to create raw sockets without sudo
aagbsn wrote a set of patches to let network tests discover if they need the ability to create raw sockets and added instructions for doing setcap on the python interpreter binary to enable a user to create raw sockets without giving sudo to ooniprobe.
however, we don't want to ask a user to do this to their system python interpreter. what we need is a virtualenv setup script which creates an entirely new copy of the python interpreter to use setcap on.