DB/SAI: Convert a core script to SAI. Fixes issues when abandoning the quest.

Thanks @dr-j for the initial work.
DB/Quests: Fix Bringing Down Heb'Jin, closes #376
Remove BOM
Merge pull request #9626 from LeGuybrush/master

Remove BOM
Script/Spell: Apply Frost Imbued Blade only in 25 man mode

Note: Quest credit spells are already casted in 25 man mode only.
Script: Remove unnecessary constant
Remove BOM
Scripts/Pit of Saron: Changed Overlord's Brand script to be safer

Closes #9125
Scripts/Quest: Fix "Massacre At Light's" after recent vehicle changes and drop some silly code

Closes #9448
Merge pull request #9632 from joschiwald/scriptfix

Scripts/Quest: Fix "Massacre At Light's" after recent vehicle changes an...
Script/SAI: Remove Shadow's Edge on completing 'Shadowmourne...'

Closes: #9600
DB/Misc: 2 updates to fix non working SAI scripts

Closes #9460
DB/Misc: Doing this out of the kindness of my heart, not because @Aokromes forced me into slavery.

Closes #9624
Script/SAI: Convert Arzeth the Merciless to SAI
Script/SAI: Fix runtime errors
Rename sql files from previous commit and add new line at eof
Core/Buildsystem: Actually follow CONF_DIR path-directive when installing configuration-files on UNIX
Fixes issue #9649
DB/Quests: Fix The Leaders at Jin'Alai, closes #902

Remove some double spawns
Add some missing spawns
Convert some EAI to SAI
Add some visual effects for quest Breaking Through Jin'Alai
Merge branch 'master' of https://github.com/TrinityCore/TrinityCore into TrinityChat2