Remove duplicate FAQ; remove redirect TODO

[lizadaly]

H2O has two FAQs; this removes the unmaintained one in the webapp in favor of the one on the static site.

• Removes some old TODOs about migrating the static pages to a different URL root; that seems like it's not necessary.
• Changes the direct link in the footer to the static site
• Changes the entry in urls.py to the static site as a permanent redirect (for anyone pointing at it inbound)
• Makes the subscribe redirect a permanent 301 (just seems like the right call here).