Allow configuring the listen host (#9924)

.config/example.yml

@@ -30,6 +30,9 @@ url: https://example.tld/
 # The port that your Misskey server should listen on.
 port: 3000
 
+# The hostname or address to listen on (default: all)
+#host: "127.0.0.1"
+
 #   ┌──────────────────────────┐
 #───┘ PostgreSQL configuration └────────────────────────────────