lmdb: use 8-byte keys instead of 32, use indexAddr, migrations.

helpers.go

@@ -0,0 +1,8 @@
+package eventstore
+
+import "github.com/nbd-wtf/go-nostr"
+
+func isOlder(previous, next *nostr.Event) bool {
+	return previous.CreatedAt < next.CreatedAt ||
+		(previous.CreatedAt == next.CreatedAt && previous.ID > next.ID)
+}