Add Wikibase Repository and Client extensions

[fredster33]

[MatmaRex]

I'll be happy to add them if someone figures out the minimal configuration necessary to make them work and proposes a patch.

[lucaswerkmeister]

I think this should work as a minimal Wikibase configuration:

wfLoadExtension( 'WikibaseRepository', "$IP/extensions/Wikibase/extension-repo.json" );
require_once "$IP/extensions/Wikibase/repo/ExampleSettings.php";
wfLoadExtension( 'WikibaseClient', "$IP/extensions/Wikibase/extension-client.json" );

But we’re hoping to reduce that further by making the ExampleSettings.php unnecessary (see T291617).

I wonder if it also makes sense to load Wikibase’s CI settings (which, among other things, enable several experimental features that aren’t enabled by default yet, but which users might want to test on patch demo). I think a few other extensions also have CI-only settings; does Patch Demo usually load these or not?

[MatmaRex]

I think a few other extensions also have CI-only settings; does Patch Demo usually load these or not?

The only one I'm aware of is GrowthExperiments, and Patch Demo loads its CI-only settings.

In general I think you should do whatever makes it easiest to test patches most of the time. If the experimental features won't be too disruptive for someone trying to test a typo fix, then enable them.