Integrate CSS components from style guide

* Big numbers
* Margins
* Semantic shim for Bootstrap
Move things out into partials

* It was getting a little bit big in sites/show.html.erb
* Add the muted-text for mapping count
Remove Mappings/Analytics links from orgs#show

(in favour of a single link to the site dashboard)
Site#transition_status should be a symbol
Show 'overdue' status when status and launch date don't agree

* Avoids mixed messages
Cope with missing launch dates
Remove <br> from site dashboard transition date