Removed duplicate code from the Cool Event NPCs

- Moved common code to a function.
- Modified to use appropriate functions from function_kafras.txt.
- Modernized syntax/updated function documentation in both files.
- Fixed the Rachel NPC incorrectly stating it's warping you to Rachel,
  instead of Veins.
- Special thanks to jaBote, GubA.

Signed-off-by: Haru <haru@dotalux.com>