[TW278] - Core/Scripts: Prevent multiple spawns of Ulag

http://www.wowhead.com/quest=1819/ulag-the-cleaver
Scripts/Commands: Ensure gameobject template is valid from .gob add temp [...]

As per Aokrome's spamming. "Avoids false positive logs"
DB/Item: Fix Essence of the Pure Flame scaling

By gecko32, closes #1925
Core/Spells: Fixed players being able to mount with all transform auras

Closes #11852
Merge branch 'master' of https://github.com/TrinityCore/TrinityCore