Add script for Tortured Druids/Sentinel in Silithus

* They will now emote and spawn a Hive'Ashi Drone on death (75% chance).
* Tortured druid also had its combat AI added.
All spell IDs are correct.
Timers and threshold for tortured druid are guesswork (probably close to
correct) based on similar NPCs scripts.

Thanks Metalica for his contribution.

Related to Classic DB issue:
https://github.com/classicdb/database/issues/653