Bundle all scripts and runtime virtual env.

[ccoulombe]

Support running from a virtual env. as a script. Include run_alphafold.py and download scripts as well.

Bundle all scripts inside a wheel. This ease distribution and lets a user install the wheel inside his virtual environment.

[google-cla[bot]]

Thanks for your pull request! It looks like this may be your first contribution to a Google open source project. Before we can look at your pull request, you'll need to sign a Contributor License Agreement (CLA).

View this failed invocation of the CLA check for more information.

For the most up to date status, view the checks section at the bottom of the pull request.