feat: Users API, ownership transfer and removal of the legacy role string

internal/domain/role/roleRepositoryInterface.go

@@ -9,4 +9,5 @@ type Repository interface {
 	Delete(id uint32) error
 	ReassignMembers(from uint32, to uint32) (int, error)
 	RemoveTypedGrants(typeKey string) (int, error)
+	MemberCounts() (map[uint32]int, error)
 }