Updated mediawiki/extensions
Project: mediawiki/extensions/Wikibase  56050dbf6f6e5941adbe57feeddc2006f689acd9

Move data model classes into its own component

This will make the data model boundary more clear and allow us to easily
identify messed up dependencies and responsibilities that have crept into
data model classes while they dont belong there.

Change-Id: Iece4a230dd475653af0beeab7ce72abd94dbb676