added 4 agile questions to agile-quiz.ts

[IntelliJinceTech]

Summary of changes

• Added 4 agile questions in relation to burndown/burnup charts and non-functional requirements
• Issue Adding Agile questions to quiz site #103

Checklist

• I have read and followed the contribution guidelines.
• I have read through the Code of Conduct and agree to abide by the rules.
• This PR is for one of the available issues and is not a PR for an issue already assigned to someone else.
• My PR title has a short descriptive name so the maintainers can get an idea of what the PR is about.
• I have provided a summary of my changes.

closes #XXXXX

[jdwilkin4]

Thank you for your contribution!

Please review the requested changes.
Once those changes have been implemented, then we can merge your PR into main. 👍

[IntelliJinceTech]

Thank you for your contribution!

Please review the requested changes. Once those changes have been implemented, then we can merge your PR into main. 👍

Thanks for reviewing and have updated the PR accordingly!

[jdwilkin4]

Congrats on another contribution to our repository. 🎉
We look forward to future contributions. 👍