move nettree to its own place. various other changes

data/.rpsl

@@ -5,5 +5,9 @@ default-owner:    DN42-MNT
 network-owner:    inet6num inet6num
 network-owner:    inet6num route
 network-owner:    inet6num inetnum
-network-owner:    inetnum inetnum
-network-owner:    inetnum route
+network-owner:    inetnum  inetnum
+network-owner:    inetnum  route
+primary-key:      inetnum  cidr
+primary-key:      inet6num cidr
+primary-key:      person   nic-hdl
+primary-key:      role     nic-hdl

data/schema/NAMESPACE-SCHEMA

@@ -1,9 +1,10 @@
 schema:             NAMESPACE-SCHEMA
-ref:                dn42.schema
+ref:                dn42.namespace
 key:                namespace     required single   primary schema > [name]
 key:                ns-schema     required single   > [schema]
 key:                ns-owner      required single   > [schema]
 key:                default-owner optional single   lookup=dn42.mntner  > [mntner]
 key:                network-owner optional multiple > [parent-schema] [child-schema]
+key:                primary-key   optional multiple > [schema] [primary]
 mnt-by:             DN42-MNT
 source:             DN42