fix: Different ratelimits for the same route (implement discord buckets) (#1546)

* Don't disable when there's no resetTick

Sometimes Discord won't send any ratelimit headers, disabling the semaphore for endpoints that should have them.

* Undo changes and change comment

* Add HttpMethod to BucketIds

* Add X-RateLimit-Bucket

* BucketId changes

- BucketId is it's own class now
- Add WebhookId as a major parameter
- Add shared buckets using the hash and major parameters

* Add webhookId to BucketIds

* Update BucketId and redirect requests

* General bugfixes

* Assign semaphore and follow the same standard as Reset for ResetAfter

src/Discord.Net.Core/RequestOptions.cs

@@ -1,3 +1,4 @@
+using Discord.Net;
 using System.Threading;
 
 namespace Discord
@@ -57,7 +58,7 @@ namespace Discord
 		public bool? UseSystemClock { get; set; }
 
         internal bool IgnoreState { get; set; }
-        internal string BucketId { get; set; }
+        internal BucketId BucketId { get; set; }
         internal bool IsClientBucket { get; set; }
         internal bool IsReactionBucket { get; set; }