feat: keep addresses for longer (#207)

There's really no reason to expire these after 10 minutes as opposed to
30. Given that our default DHT refresh interval is 10 minutes, setting
this to 30 reduces the chances that we'll "forget" peers.

core/peerstore/peerstore.go

@@ -28,14 +28,14 @@ var (
 	// ProviderAddrTTL is the TTL of an address we've received from a provider.
 	// This is also a temporary address, but lasts longer. After this expires,
 	// the records we return will require an extra lookup.
-	ProviderAddrTTL = time.Minute * 10
+	ProviderAddrTTL = time.Minute * 30
 
 	// RecentlyConnectedAddrTTL is used when we recently connected to a peer.
 	// It means that we are reasonably certain of the peer's address.
-	RecentlyConnectedAddrTTL = time.Minute * 10
+	RecentlyConnectedAddrTTL = time.Minute * 30
 
 	// OwnObservedAddrTTL is used for our own external addresses observed by peers.
-	OwnObservedAddrTTL = time.Minute * 10
+	OwnObservedAddrTTL = time.Minute * 30
 )
 
 // Permanent TTLs (distinct so we can distinguish between them, constant as they