Plugg update

[georgelgeback]

This passes the tests when the backend changes are used. I've even tested this on different screen sizes (wow)!

Adds:

• Plugg pages, admin and public
• Plugg pages should use plugg.fsektionen.se instead of fsektionen.se/plugg, we need to test if this actually works (same tech on stage)
• Update to use new api error so we get and can use numeric error codes (e.g. 404)

Relies on:

• Plugg update WebWebWeb#527