Document Tiered integration (v2.1.0) Adds Developer-Tiered-Integration and Player-Tiered pages, and updates Developer-Datapack-Creation, Developer-Architecture, Developer-Guide, Player-Guide, Player-Configuration, Player-Compatibility, Home, and _Sidebar to reflect the Tiered merge. Co-authored-by: Copilot App <223556219+Copilot@users.noreply.github.com>