Implements two standard features of the Auction House.
* GetAll scan, retrieves all auctions and sends them in a single packet.
There's a limitation on how often a player can do this (Max 55000 items)
* Search throttling. For normal searches, the server can send a time
in milliseconds to the client, the client will wait that long between
searches. Delay set in config
Closes#16469
(cherry picked from commit 3aaeb574050668e5a240078f6e40337c3975d110)
If there is an alive instance of the creature upon creature spawn, skip
spawn entirely. If there are only dead instances, despawn them. A new dead
corpse in the creatures home position will be respawned.
Closes: #16462
(cherry picked from commit fe2a0fda4464effeb2fb655da84a0460328b1aeb)
pete318