feature/conn25: use new pool nodeattr

We have been reading the pool config from the app nodeattr, but it is
global config, not per app, so it needs to be its own thing.

Updates tailscale/corp#39999

Signed-off-by: Fran Bull <fran@tailscale.com>

types/appctype/appconnector.go

@@ -104,7 +104,10 @@ type Conn25Attr struct {
 	// Connectors enumerates the app connectors which service these domains.
 	// These can either be "*" to match any advertising connector, or a
 	// tag of the form tag:<tag-name>.
-	Connectors      []string         `json:"connectors,omitempty"`
+	Connectors []string `json:"connectors,omitempty"`
+}
+
+type Conn25PoolsAttr struct {
 	V4MagicIPPool   []netipx.IPRange `json:"v4MagicIPPool,omitempty"`
 	V4TransitIPPool []netipx.IPRange `json:"v4TransitIPPool,omitempty"`
 	V6MagicIPPool   []netipx.IPRange `json:"v6MagicIPPool,omitempty"`