In order to have more fine-grained control on the network saturation between the edge and the swift backends for upload.wikimedia.org, implement a rate-limiting solution, partly based on the work already done for T399291: Epic: API Rate Limiting Architecture

The ratelimit will be enforced by the envoy instances fronting the ms-fe swift servers, backed by a standalone ratelimit service identical to the one used by the mesh for internal rate limiting.

As the goal is to limit the bandwidth used and that is not directly related to the number of requests, we will implement cost-based rate limiting T399844: Investigate feasibility of cost-based rate-limiting with Envoy using the response size as the cost function.