without key encryption at rest, reimplement with a custom Device class

@@ -0,0 +3,4 @@
+
+A new {{ device_type }} multi-factor authenticator has been added to your Blender ID account {{ user.email }}
+
+If this wasn't done by you, please reset your password immediately and contact blenderid@blender.org for support.

@@ -0,0 +79,4 @@
+  <p>
+    Store your recovery codes safely (e.g. in a password manager or use a printed copy) and don't share them.
+    Each code can be used only once.
+    You can generate a new set of recovery codes at any time, any remaining old codes will become invalidated.

@@ -0,0 +69,4 @@
+        for device in devices_for_user(self.request.user):
+            device.delete()
+        if self.request.user.confirmed_email_at:
+            bid_main.tasks.send_mfa_disabled_email(self.request.user.pk)

@@ -0,0 +82,4 @@
+        ):
+            # Forbid setting up recovery codes unless the user already has some other method
+            return HttpResponseBadRequest("can't setup recovery codes before other methods")
+        user.staticdevice_set.all().delete()

@@ -0,0 +94,4 @@
+class InvalidateRecoveryView(mixins.MfaRequiredIfConfiguredMixin, View):
+    def post(self, request, *args, **kwargs):
+        user = self.request.user
+        user.staticdevice_set.all().delete()

@@ -0,0 +139,4 @@
+class U2fRegisterView(mixins.MfaRequiredIfConfiguredMixin, FormView):
+    form_class = U2fRegisterForm
+    success_url = reverse_lazy('bid_main:mfa')
+    template_name = "bid_main/mfa/u2f_register.html"

@@ -0,0 +132,4 @@
+        self.clean_agent()
+        return self.cleaned_data
+
+    def save(self):