issue #145 fix to use any static backup device instead of strictly named

[nnseva]

Description

Now any static OTP device can be used as a backup OTP device instead of one strictly having the name 'backup'.

Motivation and Context

The django_otp.plugins.otp_static package has a management command addstatictoken to create a special backup static token that could be used for the OTP backup process.

As described in issue #145 the addstatictoken creates a static device named differently from the static device default name used in the two_factor package, if no other backup devices are present for the user yet. Because of that, no backup button is shown while login in when the backup code has been created by the addstatictoken management command.

How Has This Been Tested?

Two unit tests have been created altering backup static OTP device names in existing ones.

You can check working the patch yourself. Create your own project using the package, and look at the login process. An unpatched package doesn't show the backup button if the backup code has been created by the addstatictoken management command, while the patched one does.

Types of changes

• [x] Bug fix (non-breaking change which fixes an issue)
• [ ] New feature (non-breaking change which adds functionality)
• [ ] Breaking change (fix or feature that would cause existing functionality to change)

Checklist:

• [x] My code follows the code style of this project.
• [ ] My change requires a change to the documentation.
• [ ] I have updated the documentation accordingly.
• [x] I have added tests to cover my changes.
• [x] All new and existing tests passed.