Fix database connection pool contention (maybe)

Instead of acquiring a connection per service per request, we
acquire connections more often but at a more granular level, meaning
they're also disposed of more quickly instead of staying for a long time
in case of long-running commands or leaks.

PluralKit.Bot/Utils.cs

@@ -152,14 +152,12 @@ namespace PluralKit.Bot
     /// Subclass of ICommandContext with PK-specific additional fields and functionality
     public class PKCommandContext : SocketCommandContext
     {
-        public IDbConnection Connection { get; }
         public PKSystem SenderSystem { get; }
         
         private object _entity;
 
-        public PKCommandContext(DiscordSocketClient client, SocketUserMessage msg, IDbConnection connection, PKSystem system) : base(client, msg)
+        public PKCommandContext(DiscordSocketClient client, SocketUserMessage msg, PKSystem system) : base(client, msg)
         {
-            Connection = connection;
             SenderSystem = system;
         }