Docs open sourced

[Jeff Kaufman]

The user-facing documentation for modpagespeed is now open source:

https://github.com/pagespeed/mod_pagespeed/tree/master/doc

You can see it live at:

https://modpagespeed.com/doc

I'm going to set up redirects from the old
https://developers.google.com/speed/pagespeed/module/ documentation
site, but I haven't done this yet.

If you have any doc edits to make, send a pull request! (Or you can
let me know about things and I can fix them.)

Note: doc changes don't go live on submit. After submitting, someone
needs to do:

ssh modpag...@modpagespeed.com
cd ~/doc/mod_pagespeed
git pull

Jeff