Document opts

[jmglov]

There are a lot of config options, mostly optional with sensible defaults. I'd like to document them so that you can run bb help and get something like this:

quickblog can be configured by passing an options map to API functions:

:blog-title        title of the blog; default: "quickblog"
:blog-author       blog author's name; default: "Quick Blogger"
:blog-description  description of the blog; default: "A blog about blogging quickly"
:blog-root         link to the root of the blog; default: "https://github.com/borkdude/quickblog"
:about-link        [optional] link to an about the author page
:discuss-link      [optional] link to discussion forum for the blog
:twitter-handle    [optional] Twitter handle to link to
...