m/n/c/curator: add UpdateStatus

This implements Curator.UpdateStatus, which lets nodes self-report some
status items. Currently this is their external IP address, which is
needed to generate a Cluster Directory which is in turn needed to
register into a cluster.

Change-Id: Ib5464ca78ee3466d9b9f89b7af8b40f613ae8dcc
Reviewed-on: https://review.monogon.dev/c/monogon/+/332
Reviewed-by: Lorenz Brun <lorenz@monogon.tech>
diff --git a/metropolis/node/core/rpc/server.go b/metropolis/node/core/rpc/server.go
index 70a0a74..0e823f4 100644
--- a/metropolis/node/core/rpc/server.go
+++ b/metropolis/node/core/rpc/server.go
@@ -12,6 +12,7 @@
 	// services, either locally or remotely.
 	nodePermissions = Permissions{
 		epb.Permission_PERMISSION_READ_CLUSTER_STATUS: true,
+		epb.Permission_PERMISSION_UPDATE_NODE_SELF:    true,
 	}
 )