Scripts/Ulduar: Fix Algalon the Observer outro phase(fixes kill credit and some achieves).
DB/Creature: spawn Stabled Argent Warhorse

By Foldor, closes #11479, updates #11043
DB/Creature: Fix another trigger visible to players
DB/Creature: Delete some double spawns

Updates #1515
DB/Reputation: Fix Oracle and Frenzyheart Tribe reputation

Closes #11106
Core/LFR: Fix a theoretical error with item_level
Despite the check never happening (player->GetAverageItemLevel() < 0 is impossible), it is more efficient.
Also improves codestyle consistency. Original fix by @emsy.
Merge pull request #11616 from Ascathor/master

Core/LFR: Fix a theoretical error with item_level
DB/Creature: Correct Felmist gas cloud model
Misc Move file to proper place
Core/Chat: Fix BuildChatPacket calls so scripts that use OnPlayerChat can actually change the text

Closes #11625