exchanges/request: abstract and consolidate rate limiting code to request package (#1477)

* initial consolidation of rate limiting code to request package to reduce bespoke code implementation

* continued

* finish abstraction

* lint

* exchanges: fix tests

* linter: fix

* poloniex: fix auth rate limit not being set

* ratelimiter: convert from token to weight

* glorious: nits addressed with fire

* linter: rip

* change func name set -> get

* fix test

* derbit: impl

---------

Co-authored-by: Ryan O'Hara-Reid <ryan.oharareid@thrasher.io>

exchanges/bithumb/bithumb_wrapper.go

@@ -114,7 +114,7 @@ func (b *Bithumb) SetDefaults() {
 	}
 	b.Requester, err = request.New(b.Name,
 		common.NewHTTPClientWithTimeout(exchange.DefaultHTTPTimeout),
-		request.WithLimiter(SetRateLimit()))
+		request.WithLimiter(GetRateLimit()))
 	if err != nil {
 		log.Errorln(log.ExchangeSys, err)
 	}