Add packets-per-second measuring to DME

[hashsploit]

Add a feature to Clank's DME server to measure the packets-per-second between players in a game world.

This would be useful as it can be used to check for "frame limit disabling" (PCSX2) or cheating via packet manipulation. This value should be exposed to the Lua plugin API along with other player information. The following values should be considered in a Lua plugin that handles packets-per-second moderation:

• pps_lower_limit - The lower bound of normal packets-per-second expected. (this will probably be 0 unless the client is expected to never have hick-ups).
• pps_upper_limit - The upper bound of normal packets-per-second expected. (this might be different per title and should be a high value at first for example 100 and then lowered slowly each test until it leaves enough room for some expected latency).
• pps_maximum - The absolute hard maximum number of packets a client may send. (this might be used to kick a player and log a WARN message to the console for sys admins to review).

Anything outside the pps_lower_limit and pps_higher_limit bounds should be considered abnormal client behavior, however this also depends on client latency. We want to try to avoid flagging players who are lagging because of poor internet connectivity. Where the pps_maximum value is set to a high value that is triggered only when we are certain the player is modifying the game's normal functionality.