Take the Tor exit list from Onionoo, which has the IPv6 exits (closes #234)

`check.torproject.org` lists IPv4 exits only, so `is_tor` was false for an IPv6 exit. `tor_exits` now comes from Onionoo through a new format that reads `relays[].exit_addresses` and `relays[].or_addresses`. IPv6 addresses come only from `or_addresses`, the address a relay accepts Tor connections on, so an exit leaving from another IPv6 address still has `is_tor` false.

Judgement call: a document with no addresses fails the parse.
Rule suppressed: `tagliatelle` on the struct holding Onionoo's field names.

Model: opus-5-5

internal/iplist/lists.go

@@ -28,8 +28,9 @@ const (
 	// https://www.spamhaus.org/blocklists/do-not-route-or-peer/
 	spamhausDROPInterval = 24 * time.Hour
 
-	// Tor publishes a new exit list every hour and sets no download limit:
-	// https://collector.torproject.org/recent/exit-lists/
+	// Onionoo's relay data follows Tor's hourly network consensus, and
+	// Onionoo sets no download limit:
+	// https://metrics.torproject.org/onionoo.html
 	torExitsInterval = time.Hour
 )
 
@@ -88,9 +89,10 @@ func Lists() []List {
 		{
 			Name:        TorExitsList,
 			Description: "A Tor exit node, where traffic from the Tor network leaves",
-			URL:         "https://check.torproject.org/torbulkexitlist",
-			Interval:    torExitsInterval,
-			Format:      FormatLines,
+			URL: "https://onionoo.torproject.org/details?" +
+				"flag=Exit&running=true&fields=exit_addresses,or_addresses",
+			Interval: torExitsInterval,
+			Format:   FormatOnionooJSON,
 		},
 	}
 }