[Quest API] Add Despawn Events to Perl/Lua. (#2707)

# Perl
- Add `$bot->GetBotID()`.
- Add `EVENT_DESPAWN`.
- Add `EVENT_DESPAWN_ZONE`.

# Lua
- Add `bot:GetBotID()`.
- Add `event_despawn`.
- Add `event_despawn_zone`.

# Notes
- Allows operators to determine when a Bot or an NPC has been despawned via Depop.
- Bots call NPC::Depop on ^camp so we just put the code there.
- Adds the ability to get a bot's ID using their reference in case you're looping a list and need that value.
- Moves `DispatchZoneControllerEvent` from NPC to Mob so it can be used by any type.

zone/event_codes.h

@@ -109,6 +109,8 @@ typedef enum {
 	EVENT_PAYLOAD,
 	EVENT_LEVEL_DOWN,
 	EVENT_GM_COMMAND,
+	EVENT_DESPAWN,
+	EVENT_DESPAWN_ZONE,
 #ifdef BOTS
 	EVENT_SPELL_EFFECT_BOT,
 	EVENT_SPELL_EFFECT_BUFF_TIC_BOT,