Realign def method block
Use new content_api_has_countries helper and Time pre-processing

The Content API wrapper provided by GDS API Adapters now parses the
'updated_at' values for country results to Time objects. Don't
explicitly parse Strings to DateTime objects. This is already done for
us now.
Provide times for all stubbed content api responses
Sort countries by date in an immutable way rather than destructively
Provide a real response data structure rather than being lazy
Add helper to convert Time objects to the String format we require
Show top 5 recently updated countries

From the list of sorted countries, take the first five to show more
metadata about when they were changed.
Bump gds-api-adapters to 4.6.0

This is to pick up the changes to how test helpers work and how the
content api response is pre-processed.
Hook up styles for country filter

Uncomment the HTML form filter and add in styles to match the design.
Make sure the country filter is visible
Provide a hard-failing test for when no matches found

When no countries are found, there should be no countries visible.
Show only one country when only a single letter matches
Use readable variables for function signatures in jQuery

Most devs might not be familiar with the function (a, i, m) idiom for
building out jQuery expressions. To prevent any confusion, provide
specific names for these variables.
Make sure that the grouping also alphabetises as well

Grouping by letter will just lazily group by first seen country.
Instead we want to sort the list by the name first and then group.
Be consistent with function style
Be consistent with 'visible: true' style
Countries are already sorted by the API don't sort where unnecessary

The 'sort by date' operation should be made more explicit and
shouldn't worry about nil 'updated_at' values.
Only group countries by first character, don't sort them
Remove test for API calls which return countries without 'updated_at' set
Make recently updated countries tests assert the order of output