Consolidate hub type definitions into their own files

Move Organization, Identity, TrustCenter, and Viewer definitions to
include all their connection fields directly, removing all extend type
blocks for these hub types from entity files.

This eliminates the Relay schemaExtensions constraint where extend type
could only target types defined in the main schema file. Entity files
now only define their own standalone types and extend type Mutation.

Signed-off-by: Émile Ré <emile@getprobo.com>

pkg/server/api/console/v1/graphql/rights_request.graphql

@@ -1,13 +1,3 @@
-extend type Organization {
-    rightsRequests(
-        first: Int
-        after: CursorKey
-        last: Int
-        before: CursorKey
-        orderBy: RightsRequestOrder
-    ): RightsRequestConnection! @goField(forceResolver: true)
-}
-
 enum RightsRequestType
     @goModel(model: "go.probo.inc/probo/pkg/coredata.RightsRequestType") {
     ACCESS