DB/Quests: Amphitheater of Anguish in Zul'Drak (Thx malcrom)

- DB/Gossip: Add: Missing gossip for Gurgthock
- DB/Creature: Add: Missing spawns for Amphitheater of Anguish
- DB/Creature: Add: Missing text for Amphitheater Vendor
- DB/Waypoints: Add: Waypoints for two Amphitheater Vendors (30098)