Fix some template errors and 2FA

[A-dead-pixel]

Closes #241.

As in the commit message:

• fix 2FA by updating a template
• remove a broken, unused template
• move a portal-related template to the portals app

I'm not sure about what to do with 2FA: should all templates be updated or only the broken one? (for now I chose the latter) We could also remove the ones without our changes, though that could break someday.