p2p: fix logspam (tendermint#9756)

Since starting off as a wee validator, I've been mystified by the volume of p2p logspam, which often makes it impossible to monitor other tasks. Thus, routine p2p events, have been cast into the land of debug.

---

#### PR checklist

- [x] Tests written/updated, or no tests needed
- [x] `CHANGELOG_PENDING.md` updated, or no changelog entry needed
- [x] Updated relevant documentation (`docs/`) and code comments, or no
      documentation updates needed

p2p/switch.go

@@ -726,7 +726,7 @@ func (sw *Switch) addOutboundPeerWithConfig(
 	addr *NetAddress,
 	cfg *config.P2PConfig,
 ) error {
-	sw.Logger.Info("Dialing peer", "address", addr)
+	sw.Logger.Debug("Dialing peer", "address", addr)
 
 	// XXX(xla): Remove the leakage of test concerns in implementation.
 	if cfg.TestDialFail {
@@ -854,7 +854,7 @@ func (sw *Switch) addPeer(p Peer) error {
 		reactor.AddPeer(p)
 	}
 
-	sw.Logger.Info("Added peer", "peer", p)
+	sw.Logger.Debug("Added peer", "peer", p)
 
 	return nil
 }