Core/Scripts: Remove database spell script system

[offl]

Changes proposed:

• Remove spell_scripts

Issues addressed:

none

Tests performed:

builds, started worldserver, tested if event_scripts and waypoint_scripts are still functional, checked if no errors created

[CraftedRO]

I guess might worth mentioning that this https://github.com/TrinityCore/TrinityCore/pull/31471 should be merged first, just in case.