User satisfaction markup injected by survey script

Previously, the markup was included in the base template all the time.
Apart from being an extra bit of markup in every request, this was also
causing issues with unusual clients, search spiders, etc.

This leaves only a wrapper with no content in the base template, and puts
the markup into the survey script. Since this script is going to be cached
by clients.
Add ari-hidden attributes to survey bar.
Merge pull request #438 from alphagov/include-survey-markup-with-script

User satisfaction markup injected by survey script
Serve govuk-component documentation as JSON

Previously this documentation was stored in the govuk_component_guide app and was
frequently out of sync with static, or failed if pointing at a different static
endpoint.

This moves the documentation into static and exposes it as an API-like endpoint,
so that the documentation data could be auto generated in the future, rather than
a static file.
Merge pull request #439 from alphagov/component-documentation-api

Serve govuk-component documentation as JSON
Update all instances of greys in static to use either semantic
colour variables from the toolkit or nearest toolkit grey

• rationalised corresponding grey
• update to semantic variables
• update grey variables to match toolkit rather than static colours
Remove import refernce to local static colours file

• remove reference
• delete _colours.scss

https://www.agileplannerapp.com/boards/105200/cards/5541