fix: the views that take a password or a key keep it out of error reports

No view used sensitive_post_parameters, so once ADMINS is set the error
mail of a failing POST would carry the password or key in plain text.
The user create, edit and password views, the password change, the
compute forms, the host secrets, the VM's root password and its console
settings now mark their POST data sensitive.

admin/views.py

@@ -15,6 +15,7 @@ from django.utils import timezone
 from django.utils.http import url_has_allowed_host_and_scheme, urlencode
 from django.utils.translation import gettext_lazy as _
 from django.views.decorators.http import require_POST
+from django.views.decorators.debug import sensitive_post_parameters
 from instances.models import InstanceTombstone
 from instances.report import workbook
 from logs.audit import audit, changed_fields, snapshot
@@ -124,6 +125,7 @@ def user_list(request):
     )
 
 
+@sensitive_post_parameters()
 @superuser_only
 def user_create(request):
     user_form = forms.UserCreateForm(request.POST or None)
@@ -149,6 +151,7 @@ def user_create(request):
     )
 
 
+@sensitive_post_parameters()
 @superuser_only
 def user_update(request, pk):
     user = get_object_or_404(User, pk=pk)
@@ -190,6 +193,7 @@ def user_update(request, pk):
     )
 
 
+@sensitive_post_parameters()
 @superuser_only
 def user_update_password(request, pk):
     user = get_object_or_404(User, pk=pk)