Switching master to v1

[AlaaSarhan]

Todo:

• [x] update Readme to reflect the new status
• [x] configure a live demo (will be static site on heroku for now, deployable on pushes to master)
• [x] add Heroku API token to secrets and test automatic deployment
• [x] switch gh deploy action to use master branch
• [x] add elements for a test case "build a window with a confirmation dialog for closing it":
  • [x] Window element
  • [x] Text element with multiline support
  • [x] Button element
  • [x] duplicate element function