common/per_per_state: generalize lightningd/peer_comm Part 1

Encapsulating the peer state was a win for lightningd; not surprisingly,
it's even more of a win for the other daemons, especially as we want
to add a little gossip information.

Signed-off-by: Rusty Russell <rusty@rustcorp.com.au>

tools/generate-wire.py

@@ -42,6 +42,7 @@ varlen_structs = [
     'utxo',
     'bitcoin_tx',
     'wirestring',
+    'per_peer_state',
 ]