Create custom authentication application for autoreduction webapp

[MarcusNoble]

Create an authentication backend for Django that makes use of ICAT authentication and sessions.

See ​https://docs.djangoproject.com/en/dev/topics/auth/customizing/ for details.

• Upon first login the user should be created in the 'user' table. A check for if the user is staff (instrument scientist) could also be done at this point. Superusers must be manually set Superusers will be set based on a check for ICAT user group. The password field should be blank(if possible?) so that the authentication always goes off to ICAT.

• A method decorator should be used on all method that require the user to be logged in (pretty much all) that makes a call to checkSession(). This needs to be in addition to the @login_required decorator as that doesn't check for invalidation of the session provided by the UOWS.

For Tester:

Note: This can only be done by a new user.

1. Navigate to ​http://datareducedev.isis.cclrc.ac.uk/autoreduce_webapp/runs/queue/, when asked for credentials login with your Federal ID details. (If these details don't work please let me know)
2. You should be redirected to a mostly blank page but it should read "Welcome, [name]" in the top bar.
3. In a new tab navigate to ​https://devusers.facilities.rl.ac.uk/auth/ and click the logout link in the top right.
4. Refresh ​http://datareducedev.isis.cclrc.ac.uk/autoreduce_webapp/runs/queue/ and you should be asked to login again.

[MarcusNoble]

• There is currently some issues with infinite redirects when django appends ?next=.
• The logout method is returning users to users.facilities.rl.ac.uk/auth (with no redirect back).This may be OK when the new auth menu is rolled out with user-specific menu items (as autoreduce webapp can be one of them)