Refactor tenant schemas to hub and add hub models

Moved tenant-related schemas and documentation from the system namespace to the new hub namespace, including renaming and relocating JSON schema and Zod files. Added new hub-specific schemas for BillOfMaterials, ComposerRequest/Response, MarketplacePlugin, ProjectSubscription, DeploymentTarget, and HubProject. Updated package exports and removed system/tenant documentation and references.

Author: hotlong

content/docs/references/system/meta.json

@@ -11,7 +11,6 @@
     "organization",
     "policy",
     "role",
-    "tenant",
     "territory",
     "translation",
     "webhook"