Support wget command for anonymous-access link

[bemoody]

Currently, we allow certain people to download project files in bulk using wget.

• For active projects: the project's authors, the project's editor, and anyone with the "project.change_activeproject" permission

• For open projects: anyone

• For controlled projects: people who are credentialed and signed the DUA

People using an "anonymous access" link are permitted to download the files, but there is no convenient, officially supported way to download the files in bulk.

This should be supported, although we perhaps need to verify that the person has agreed to the Anonymous Access Data Use Agreement.