Core/Spells: move Death Knights Presences into SpellScripts, fix possible issue after spec change, and fix some startup errors

Closes #10354
Core/Spells: fix uninitialised value
DB/Conditions: Fix gossip condition for Bat Handler Camille <Bat Handler>

Closes #10240
Core/Spells: moved Improved Paladin Auras and Aura Mastery into SpellScripts

Closes #205
Closes #5163
Closes #6809
Closes #7408
Closes #9587