Remove password protection on fixture files

[dmlorenzetti]

Load a fixture file from the command line, e.g.:

openeis loaddata path-to/daily_summary_fixture.json

Now try to look at the project via the web browser (i.e., after executing "> openeis runserver"). You will be prompted for the username and password of the person who created the fixture.

As a use-case for why this is a problem, the issue arose when I wanted to verify the units for the data. I'm working on getting unit tests to run, and there are some differences, apparently related to [kW] vs [W], between the old "reference output" and the actual output the applications produce.

Of course, the developers could all agree to use a single username and password for creating fixture files. However, this seems sub-optimal for new users who download OpenEIS and would like to explore an existing project. It would be nice to tell potential users, "load this fixture file and try it out." However, to do so right now, we would have to tell them a username and password also.

Since the fixture file already carries all the project data in clear text, it seems quixotic to lock the GUI from displaying a project loaded from a fixture file. For example, in theory I could open the fixture file using a text editor, insert the hash of my own password, and then be able to load it up in the GUI.

To resolve this problem, perhaps when you load a fixture file, the user and permissions of the existing database could be retained? In this case, the fixture file might even omit the "model":"auth.user" entry altogether.

-Dave