Core/Spells: fixed wrong aura update targets
Core/Items: Refactored ItemTemplate
Tools/ConnectionPatcher: Fix build on GCC/Clang
Core/Items: remade inventory packets to new packet system
DB/CreatureText: Update Feledren the Banished's creature text with its missing sound

Closes #13732

(cherry picked from commit 249270c52c658fc1a8cca14a55ea33abc5d21855)
Core/Players: Fix a flaw as timed quests can still turn failed even if complete

(cherry picked from commit 0043a5dd2217cf8ad7cbbc903a380c8d1fb5a1bc)
Core/Opcode Add CMSG_BUY_ITEM Opcode
Merge pull request #13739 from ProjectcoreDevs/patch-1

Core/Opcode Add CMSG_BUY_ITEM Opcode
Update PLAYER_EXPLORED_ZONES_SIZE to prevent console spam on entering Draenor zones.

Signed-off-by: AriDEV <aridev666@gmail.com>
Core/Packets: moved chat packet building function to packet builder class
Core/Items: Updated item stat calculations

* Implemented item modifiers
* Implemented item bonuses
Because saving a file is hard.
Merge pull request #13740 from AriDEV/6.x

Update PLAYER_EXPLORED_ZONES_SIZE to prevent console spam on entering Dr...
Core/Items: Fixed autocomplete typo
Core: Fix non pch build
Core: Fix non pch build²
Core/Players: Fixed melee damage
Core/Items: Added item level caps
Define some opcodes
Core/Battle.net: Fixed client crashes happening when reconnecting too soon after being kicked