Fix timeout issues with fetching members via query_members

This uses the nonce field to properly disambiguate queries. There's
also some redesigning going on behind the scenes and minor clean-up.
Originally I planned on working on this more to account for the more
widespread chunking changes planned for gateway v7 but I realized that
this would indiscriminately slow down everyone else who isn't planning
on working with intents for now.

I will work on the larger chunking changes in the future, should time
allow for it.

discord/gateway.py

@@ -535,15 +535,19 @@ class DiscordWebSocket(websockets.client.WebSocketClientProtocol):
         }
         await self.send_as_json(payload)
 
-    async def request_chunks(self, guild_id, query, limit):
+    async def request_chunks(self, guild_id, query, limit, *, nonce=None):
         payload = {
             'op': self.REQUEST_MEMBERS,
             'd': {
-                'guild_id': str(guild_id),
+                'guild_id': guild_id,
                 'query': query,
                 'limit': limit
             }
         }
+
+        if nonce:
+            payload['d']['nonce'] = nonce
+
         await self.send_as_json(payload)
 
     async def voice_state(self, guild_id, channel_id, self_mute=False, self_deaf=False):