[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/lua_parser.cpp

@@ -152,7 +152,9 @@ const char *LuaEvents[_LargestEventID] = {
 	"event_aa_gain",
 	"event_payload",
 	"event_level_down",
-	"event_gm_command"
+	"event_gm_command",
+	"event_despawn",
+	"event_despawn_zone",
 };
 
 extern Zone *zone;