DB/Misc: Make invisible some visible Triggers

By untaught, closes #10648
DB/Misc: Fixes 2 innkeepers of Hallow's End event

By dr-j and untaught, closes #11108
DB/Misc: Quest item "Drain Schematics" drop

By trickerer, fixes #10394
DB/SAI: Sprouted Frond

By untaught, closes #11123
DB/SAI: Slaves of the Stormforged

By untaught, closes #10509
DB/Misc: Neltharaku

By untaught, closes #11031
DB/Loot: Voidwalker Minions are not meant to drop loot

By dr-j and Exodius closes #11012
DB/Misc: Correct some game event data

By Foldor, closes #10960
Core/Transports

* Fixed fall damage on transports while teleporting
* Fixed packets not being received by owner if sent by a controlled minion
* Fixed an issue when a teleporting transport would attempt to reload its creature passengers on old map

Closes #11140
Fixed typo in 39175ac68071a22233cb6828bfd8f2cd099861d7
Tools: Skip extracting already existing DBC files

Thanks to MacWarrior, closes #11061
Core/Transports: Fixed a few mistakes in GO passenger teleports (currently unused), thanks joschiwald for spotting them
Merge remote-tracking branch 'TrinityCore/master'