[Performance] Reworked how client to NPC aggro checks are made

- Before when reverse aggro checks were done (client to NPC), checks would happen every 750 millseconds where a client would
		check an entire entity list with distance calcs and other checks for aggro, with many clients in a zone and many NPC's this would
		add a lot of unecessary overhead. A temporary adjustment on 3/25 was made and upped the check to 6 seconds.
	- Now, there is a new methodology to scanning. The client will build a cache list of NPC's within close range as defined in new rule:
		RULE_INT(Range, ClientNPCScan, 300) and will also get any NPC that has an aggro range beyond that defined range to use in
		the frequent checks for aggro, the result is far less overhead
	- Client scanning changes when moving versus not moving, the client will scan aggro every 500 milliseconds while moving, and
		3000 millseconds aggro check when not moving, with a 6000ms re-fetch for close NPC's
	- A demo of these changes can be found here:
		https://youtu.be/aGroiwLSTVU

zone/aggro.cpp

@@ -284,7 +284,7 @@ bool Mob::CheckWillAggro(Mob *mob) {
 	if(( t1 > iAggroRange)
 		|| ( t2 > iAggroRange)
 		|| ( t3 > iAggroRange)
-		||(mob->IsInvisible(this))
+		|| (mob->IsInvisible(this))
 		|| (mob->IsClient() &&
 			(!mob->CastToClient()->Connected()
 				|| mob->CastToClient()->IsLD()