Core/Spells: Define and implement SPELL_ATTR7_NO_PUSHBACK_ON_DAMAGE
Core/GameObject: Fix crash added in c6bf7e0b1d615a22c2145c6f4a757a10a9eca92c

Thanks @jackpoz
Remove unnecessary check in previous fix
Fixed SendAddonMessage issue.

This fixes GM's not being able to send/receive addon messages through the whisper channel while accepting whispers are turned off.
DB/Creature: Fix incorrect flags_extra for 30413

By untaught, closes #12010
Core/Spells: Replace MovePosition by MovePositionToFirstCollision in spell dest target handling.

- Solves issues such as being able to summon creatures inside terrain/gameobjects, being able to fall through terrain by using Shadowstep/Feral Charge (Cat), and much more
DB/Gossip: Remove "Jarin Dawnglow <Innkeeper>" double gossip
Closes #12019
DB/Quest: The Bones of Nozronn

By phoenixfight, closes #11985
DB/Instance: Fix Ahn''Kahet exit (portal/areatrigger)
SQL: Rename in correct name
DB/Gossip: Fix some gossip in dalaran
Scripts/Duskwood: prevention to spawn multiple Twilight Corrupter and fixed some issues there
Merge pull request #12035 from MitchesD/duskwood

Scripts/Duskwood: prevention to spawn multiple Twilight Corrupter and fi...
Core/Trade: It's no longer possible to fake the amount of gold put into the trade window. It's only visual but still an exploit, allowing scamming.
DB/Misc: Delete some incorrect player_factionchange_items

Closes #12005
Scripts/HallsOfReflection: Major changes
* corrections to Intro Event (Falric, Marwyn etc.)
* fixed issues with Frostsworn General
* improved the whole Wrath of the Lich King event
* implemented outro gunship
* optimalization code and cleanup and fixed some typos
* Big thanks to @joschiwald, he is author too ;-)
Merge pull request #11960 from MitchesD/hor

Scripts/HallsOfReflection: Major changes
DB/Gameobjects: Added some missing gameobjects spawns
DB: Changed WDBVerified startdard to VerifiedBuild
DB/Gameobjects: Fixed Gymer's cage phasemask to make it appear while doing "The Storm King's Vengeance" quest