What is the context of this PR?

ONSDESYS-778

Created a new parameter search to change the structure around search functionality for better readability.
The new structure will be

 "search": {
            "id": "search",
            "navAriaLabel": 'Nav Search',
            "toggleAriaLabel": 'Toggle search',
            "form": {
                "action":  "https://www.ons.gov.uk/search" ,
                "inputName": "q",
                "inputLabel": "Search the ONS",
                "buttonText": "Search",
                "buttonAriaLabel": "Submit search"
             },
            "links": {
                'heading': 'Popular searches',
                "itemsList": [
                    {
                        "url": '#1',
                        "text": 'Cost of living'
                    },
                   ......
                ]
            }
        }

This will replace the existing searchLinks parameter which is now being deprecated and will be removed in the next major version.

As per the ticket:

• Added form element to the search input as per the ticket
• Added configurable name to the input and it defaults to q.
• Added a action param for configurable action and it defaults to ``.

How to review this PR

Check that the new functionality works as expected
Check that all tests pass

Checklist

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