Core/GameObjects: Fixed uninitialized elevator period value
Core/AH: Fix Auction House items not deleted from database

Fix some cases where Auction House items were not deleted from item_instance table of character database, for example if the owner didn't exist anymore or if the owner was the AHBot.

Updates #12699
Updates #13232
Merge branch 'master' of https://github.com/TrinityCore/TrinityCore into ghbb