Review and improve processes described in Play online.

Problem/Motivation

Improve processes described in Play online section of the documentation. This is a follow-up to the #3505721: Replace Gitpod demos.

Further ideas for improvements:

• When launching a codespace, it's a bit wird to have both "project standard" and the naked nuxt3. Is it possible to remove the project standard?
• re-evaluate whether we want to add it there or in a dedicated configurable codespace
• it would be nice to set port labels for all of them and if possible reduce ports to the ones needed
• the nuxt int he container runs in dev-mode, we should mention that, so people that might be evaluating performance are aware. off-topic though.
• The redirect from BE to FE on / is a bummer, and the documentation on it is not great. I'd at least add the ddev drush uli command to docs.
• Create a "customizable" environment with codespaces' "secrets" for possibility of custom FE repository and additional recipes
• Needs discussion: What to do with the gitpod.io links (they are still working) and devcontainer standard is supported by the gitpod flex so I guess we don't have to remove it completely.

Remaining tasks

Test and gather feedback