HTML versions of consultations

This moves a number of the publication specific functionality out into
modules so that it can also be used by consultations.

Not entirely happy with the `send` in `attachments_presenter.rb` - happy
to field alternatives. Cannot use polymorphic paths as the route names
and the paths aren't quite standard.
Add comma after HM Gov

There will always be orgs coming after it and otherwise they run into
each other.
Add some spacing to document headers on mobile

https://www.pivotaltracker.com/story/show/48922677
Don't show a pipe on the last item in list

https://www.pivotaltracker.com/story/show/48896891
Remove history link as it is a duplicate

The redirection for the link points to 1 horse guards which is the link
above. This link is no longer needed.

https://www.pivotaltracker.com/story/show/48982687
Updated datetime for roles policies list

Fixes #432
Merge pull request #515 from alphagov/html-versions-of-consultations

HTML versions of consultations

https://www.pivotaltracker.com/story/show/48888203
Merge pull request #526 from yahoopete/master

Updated datetime format for policies listed on role page

https://www.pivotaltracker.com/story/show/47839787
Factoried published policies need timestamps