sharding (blacklists): Blacklist shard support.

Moved the `user_blacklist` and `guild_blacklist` to a client TTL cache.

bot/LionModule.py

@@ -82,7 +82,7 @@ class LionModule(Module):
             raise SafeCancellation(details="Module '{}' is not ready.".format(self.name))
 
         # Check global user blacklist
-        if ctx.author.id in ctx.client.objects['blacklisted_users']:
+        if ctx.author.id in ctx.client.user_blacklist():
             raise SafeCancellation(details='User is blacklisted.')
 
         if ctx.guild:
@@ -91,7 +91,7 @@ class LionModule(Module):
                 raise SafeCancellation(details='Command channel is no longer reachable.')
 
             # Check global guild blacklist
-            if ctx.guild.id in ctx.client.objects['blacklisted_guilds']:
+            if ctx.guild.id in ctx.client.guild_blacklist():
                 raise SafeCancellation(details='Guild is blacklisted.')
 
             # Check guild's own member blacklist