Add selection of popular third party plugins

TYPO3's plugin ecosystem is one of its strength. It'd be great if the demo installation or some separate installation used popular extensions (e.g. top 20 most installed extensions).

This would allow interested users to evaluate these extensions - right now, I know no but one TYPO3 third party extension which provides a live demo.

Also, an extension-featuring demo installation can help TYPO3 admins to set up their installations by providing a reference.

Furthermore, for TYPO3 admins already using some third party extension, the demo installation can help pinpoint whether some extension's problem is due to misconfiguration or an actual extension bug.