Build ckan documentation using sphinx and upload

[rgrp]

Use python sphinx to build documenation in ./doc and then upload it somewhere publicly accessible.

NB: improving the documentation is another matter (as is integrating e.g. existing api docs).

Upload location (these are docs for CKAN codebase/concept not the ckan service at ckan.net so good not to associate it too closely with ckan.net):

• ​http://knowledgeforge.net/ckan/doc/
• (Other options: ​http://www.ckan.net/doc/ ​http://doc.ckan.net)

[rgrp]

Largely done in cset:f3782c1071cc