Add throttling to HttpApi

Use case description

Allow to set the burst and rate limits for the HttpApi. https://docs.aws.amazon.com/serverless-application-model/latest/developerguide/sam-resource-httpapi.html https://docs.aws.amazon.com/AWSCloudFormation/latest/UserGuide/aws-properties-apigatewayv2-stage-routesettings.html

Proposed solution

I would extent the DefaultRouteSettings which was introduced for the detailed metrics. (see https://github.com/serverless/serverless/pull/8510) Add parameters to the Providers.httpApi.throttle.burstLimit = 100 and Providers.httpApi.throttle.rateLimit = 100