Home button on 404 pages doesn't work

[CollierCZ]

When you arrive on a 404 page (like at https://www.writethedocs.org/conf/australia), the link in the breadcrumb and the one on the logo are both to #, which doesn't get you anywhere. This makes it harder to get out of being lost.

I'd imagine it'd be best to link to / or something, but I haven't tested in various places to see if it breaks anything. Like in the conference sites or something.

[plaindocs]

:-( we could also put some trivial index pages in those conf dirs