feat: implement addNextQuiz to automate next quiz

[wackerow]

Description

• Removes manual requirement of adding the next property value for the list of Quizzes
• Adds simple util function to add the id of the next item in the array and assign it to the next value; undefined for the final item.

Preview link

https://deploy-preview-13939--ethereumorg.netlify.app/en/quizzes

[netlify]

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