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