This starts using conditional user defaults, which were
already deployed to WMF production config.
Bug: T353225
Change-Id: I93c6efc40d1ef6c46d8711fc5a4161e5d8f683e3
Changes to the use statements done automatically via script
Addition of missing use statements done manually
Change-Id: Iad87245bf8082193be72f7e482f29e9f1bad11fc
User-options related classes are being moved to
the MediaWiki\User\Options namespace in MediaWiki Core;
reflect that change here.
Bug: T352284
Depends-On: I9822eb1553870b876d0b8a927e4e86c27d83bd52
Change-Id: Iddefd90b03a4751fce3f44e9fa0086082b21ae93