Feat/additional dataflags in datepicker

[walldenfilippa]

Description

Added yesterday, tomorrow, one year from now and one year ago as dataflags for property minDate and maxDate in Datepicker.

Note: If the date is February 29th, the one year ago option will shift to March 1st when using Typescript/setFullYear. However, when using C#/getYear, it will automatically adjust to February 28th (this is not the case here).

Related Issue(s)

• Datepicker: dynamisk styring av max og min dato #1017
• Patentstyret wishes to implement option yesterday for maxDate in Datepicker. Not an issue on the board.

Verification/QA

• Manual functionality testing
  • I have tested these changes manually
  • Creator of the original issue (or service owner) has been contacted for manual testing (or will be contacted when released in alpha)
  • No testing done/necessary
• Automated tests
  • Unit test(s) have been added/updated
  • Cypress E2E test(s) have been added/updated
  • No automatic tests are needed here (no functional changes/additions)
  • I want someone to help me make some tests
• UU/WCAG (follow these guidelines until we have our own)
  • I have tested with a screen reader/keyboard navigation/automated wcag validator
  • No testing done/necessary (no DOM/visual changes)
  • I want someone to help me perform accessibility testing
• User documentation @ altinn-studio-docs
  • Has been added/updated
  • No functionality has been changed/added, so no documentation is needed
  • I will do that later/have created an issue
• Support in Altinn Studio
  • Issue(s) created for support in Studio
  • This change/feature does not require any changes to Altinn Studio
• Sprint board
  • The original issue (or this PR itself) has been added to the Team Apps project and to the current sprint board
  • I don't have permissions to do that, please help me out
• Labels
  • I have added a kind/* label to this PR for proper release notes grouping
  • I don't have permissions to add labels, please help me out

[olemartinorg]

Sorry this took so long to review! I see the unit tests are failing here, can you double-check them? Try running yarn test dateHelpers

Also, can you make a PR for the docs for this component? 🙏