Move report-a-problem related styles to _report-a-problem.scss

This allows apps which rely solely on `header-footer-only.css` to also
get the 'report-a-problem' toggle styles.
Report-a-problem improvements

These changes in markup and styling make the report-a-problem functionality much more
self-contained, thus removing the need for apps to include custom CSS
for displaying the report-a-problem form correctly.

The report-a-problem stylesheets are also refactored to use the latest and greatest from
`govuk_frontend_toolkit`.
Merge pull request #441 from alphagov/report-a-problem-improvements

Report-a-problem improvements
New metadata component markup and Sass
Fixes to report-a-problem confirmation and errors

The markup for the report-a-problem form was changed in https://github.com/alphagov/static/pull/441
but the confirmation and error javascript code wasn't. This means that
those elements are misaligned and this change fixes that problem.
Report-a-problem: update error message copy

The support page was renamed a while ago to the contact page.
Merge pull request #445 from alphagov/report-a-problem-fixes

Report-a-problem fixes
Add basic test to ensure docs are returned

This test ensures that docs are returned when you try and request them.
As the docs controller tries to parse the JSON it also validates that
the format is correct and will fail if bad JSON is in the docs file.
Add instructions for running static locally

In particular how to have static point at it's own assets, not default to
static.dev.gov.uk, which won't exist unless you're running our whole VM stack.

This makes it easier for:
 - new devs seeing how static works
 - external contributors
 - developers of apps that depend on static (eg, may use slimmer)
Merge pull request #443 from alphagov/metadta-component

New metadata component markup and Sass
Merge pull request #446 from alphagov/how-to-run-locally

Add instructions for running static locally
Add clearing to report a problem wrapper

Without this it's breaking sticky navigation elsewhere in whitehall.
Merge pull request #448 from alphagov/fix-broken-sticky-scroll

Fix broken sticky scrolling on whitehall
Add documentation on GOV.UK Components

Static is the authorative source for components, including documentation, so should be included here.
- As this grows it might want to be split into a README in a components specific directory, tho a good one doesn't exist yet
- It might be worth creating a generator to do the creation, just docing for now
Add a rails generator for GOV.UK components

Generates all the file scaffolding, in the right places, as
the files are a bit spread throughout static at the moment.

This will include all the files required to let the component
be demo'd on govuk-component

Appending to the json docs file is a bit shonky, but we're
not planning on using that as a docs method long term. It'll
likely be inline with template, or at least one doc file per
component, which will make this simpler.
Make the GOV.UK component doc fixture structure clearer

Fixtures are a hash of hashes, the parent hash is fixture_name => fixture

The fixture is a hash of locals to be passed to the compontent view.
Update readme to include component generator