Updated authenticator TOTP

- Added security check for previouse used codes
- Allow TOTP codes with 1 step back and forward when there is a time
drift. This means in total 3 codes could be valid. But only newer codes
then the previouse used codes are excepted after that.

src/db/schemas/mysql/schema.rs

@@ -92,6 +92,7 @@ table! {
         atype -> Integer,
         enabled -> Bool,
         data -> Text,
+        last_used -> Integer,
     }
 }