Emphasise that the composable image is a Beta version on Create Apps page (comprehensive example)

[Kemi-Elizabeth]

Where on docs.platform.sh should be changed?

https://docs.platform.sh/create-apps.html

What exactly should be updated?

Add a (Beta) in the example tab for composable image in this page and also specify in the text above the example that it is a beta feature.

Additional context

See this Slack thread for context.