Remove service feedback creation URL

This functionality has now been moved over to the `support-api`.
DRY support request new forms

This change:

* makes all 'new request' forms much more uniform. There's a shared 'new' view, and all the request-specific elements are in the 'request_details' partials.
* introduces conditional logic to show guidance at the top of the form, if any is present.
Merge pull request #195 from alphagov/remove-service-feedback-posting

Remove service feedback creation URL
Merge pull request #196 from alphagov/dry-request-views

DRY support request new forms
Remove redundant heading on anonymous feedback index

Also change dev quotes to smart quotes
Move Feedex results table and paginators into partial
Anon feedback: don't display empty table

This shows a friendlier message when there's no feedback for that path
Convert page header to use the govuk_admin_template styles

This also fixes the stray border on the style guide
Merge pull request #197 from alphagov/tidy-up-anonymous-feedback-index

Tidy up anonymous feedback index
Add breadcrumbs to support requests
Add breadcrumbs for feedex pages
Merge pull request #198 from alphagov/add-breadcrumbs

Add breadcrumbs
Embed anon feedback explore form in a panel

This is done in preparation to adding more forms to the explore page.
Explore page: add guidance

This informs the Feedex users about where the feedback originates.
More appropriate naming for Explore

* Explore => ExploreByUrl (to allow addition of other explore query classes)
* Explore#by_url => ExploreByUrl#url
ExploreByUrl: move redirect path building into model

This means that the controller has to do less.
Provide more appropriate status code explore invalid
Merge pull request #199 from alphagov/tidy-explore-page

Tidy anonymous feedback explore page
Make FeedEx available to all users by default

FeedEx was initially fenced off behind a specific permission
while its usefulness was being tested. Since then, there's been sufficient
uptake of the available features to warrant a wider release.

This change allows anyone with a GOV.UK Signon account to browse
anonymous feedback left on GOV.UK.
Merge pull request #200 from alphagov/make-feedex-available-to-all-signon-users

Make FeedEx available to all users by default