Gelencsér Szabolcs / circlestack

dashboard, vm: rework Interface forms, views and operations, add UserInterface forms, views and operations; extends Interface models and views with Vxlan support

django.db.models.field.subclassing.SubfieldBase removed: https://docs.djangoproject.com/en/1.11/releases/1.10/#features-removed-in-1-10
New field classes require to call full_clean() method on Models, because the to_python() din't call automatically.
Related docs: https://docs.djangoproject.com/en/1.11/releases/1.8/#subfieldbase

dashboard, vm: fix user handling i tests, new Origin type cannot implicit convert to str, fix redirect_chain in 2FA tests, importing vm operation in __init_.py is unnecessary and and brokes the application