Create v2 files
Refactor next node
Update logic, flow and content
Add friendly time diff v2 files
Update state pension calculator

- Added 2 new questions to flow.
- Adjusted logic for outcomes.
- Change in content for questions and some outcomes.
- Adjusted tests for coverage of new flow and logic.
- Fixed leap year bug which was showing an extra day in the age output for those born on the 29th Feb in a leap year.
- Add descriptive comment to FriendlyTimeDiffV2.
Merge pull request #989 from alphagov/state-pension-calculator-update

Update state pension calculator logic and content