Fix: Packet queue adjustments

[RyanYappert]

Followup on some discussion about packet queues and handlers.

• Adjusts RequestPacketQueueHandler so that it expects a PacketQueue from its Handle.
• Adjusts the job change and equip change handlers so that they use PacketQueues and not the god awful casting that was present before.

Checklist:

• The project compiles
• The PR targets develop branch

[pacampbell]

I was looking at a private server for a different game and all packets they send use a packet queue which the handlers push into. I wonder if it makes sense to eventually move to something like that for all handlers in our server?

[RyanYappert]

I was looking at a private server for a different game and all packets they send use a packet queue which the handlers push into. I wonder if it makes sense to eventually move to something like that for all handlers in our server?

There's a ConcurrentQueue that's thread-safe and could be used for this. I assume the server object would have one, and a dedicated thread would just churn through the queue as fast as it can, rather than splitting up packet output across multiple threads. Might be a good design, but it'd definitely involve some major refactoring to that core machinery.