[SUGESTION] Strict mode for rates

[alesancor1]

Describe the solution you'd like
Currently the requests are delayed through express-slow-down when the rates (dynamic window) is not met. An optoin should be added to directly throw an error (HTTP 429) in this case instead of slowing requests down.

Describe alternatives you've considered

• Directly throw an error instead of input delay to requests.
• Add an option in configuration, like strict: true | false that allows to change the behaviour.