Remove absolute links from homepage

Use relative links instead.
Improve HTML on about page

- A document can only have one <main> element
- Fix unclosed <header> tag
- Paragraph tags cannot go inside lists
Tweak words on about page
Remove role="breadcrumbs" from breadcrumbs

I don't think role="breadcrumbs" has ever been a thing.
Remove second main element from homepage

A document can only contain one <main> element.

Re-work the styles so that the specificity still works when
we don't have another main element on the page.
Merge pull request #573 from alphagov/copyedit-homepage-about-page

Improve information pages
Number the 3 things on the about page

The horror! @jabley is not a front-ender.
Merge pull request #575 from alphagov/feature/style-numbered-points

Number the 3 things on the about page
Ammended prototype page layout

Moved two policy dashboard sections to top and shortened one of the links
Update cheapseats version

To include https://github.com/alphagov/cheapseats/pull/74
Merge pull request #577 from alphagov/enhancement/cheapseats-version

Update cheapseats version
Merge pull request #576 from alphagov/bug/policy-prototypes-amendments

Ammended prototype page layout
Pass controller maps into stagecraft api client

So that the client and server side can use independent controller mappings, and provide different code paths
Split html with newlines for easier debugging
Reorder arguments for tempalte context, so that the defaults do not override the module specifics
Add module controllers for client and server for individual modules to extend from
Add separate module views for client and server
Implemented client/server split for tab module
Remove code to stop client from rendering

If it needs to not fetch a collection, then it won't have a collection. Otherwise it should go through full render path.
Implemented client/server split for table modules