test(openchallenges): add browsers for e2e testing with Playwright to the dev container

[tschaffter]

Closes #2387

Changelog

• Add Chromium, FF and Webkit to the dev container for e2e testing with Playwright
• Use the new recommended way to install Node.js

[tschaffter]

Building the dev container shows this message. It's currently only slowing down the build by a few seconds.

 => [dev_container_auto_added_stage_label 2/8] RUN groupadd docker   && apt-get update -qq -y && export DEBIAN_FRONTEND=noninteractive   && apt-get install --no-install-recommends -qq  106.8s
 => => #                           SCRIPT DEPRECATION WARNING                                                                                                                                  
 => => # ================================================================================                                                                                                      
 => => # ▓▓▓▓▓▓▓▓▓▓▓▓▓▓▓▓▓▓▓▓▓▓▓▓▓▓▓▓▓▓▓▓▓▓▓▓▓▓▓▓▓▓▓▓▓▓▓▓▓▓▓▓▓▓▓▓▓▓▓▓▓▓▓▓▓▓▓▓▓▓▓▓▓▓▓▓▓▓▓▓                                                                                                      
 => => # ================================================================================                                                                                                      
 => => # TO AVOID THIS WAIT MIGRATE THE SCRIPT                                                                                                                                                 
 => => # Continuing in 60 seconds (press Ctrl-C to abort) ... 

This is because of node: https://stackoverflow.com/q/77021471