[Quest API] Add Entity Variable Methods to Perl/Lua. (#2579)

* [Quest API] Add Entity Variable Methods to Perl/Lua.

# Perl
- Add `$mob->GetEntityVariables()`.
- Add `$object->GetEntityVariables()`.

# Lua
- Add `mob:GetEntityVariables()`.
- Add `object:GetEntityVariables()`.

# Notes
- Convert all overloads and methods to use `std::string` for entity variables.
- Allows operators to get a list of a Mob's entity variables.

* Update loottables.cpp

zone/npc.cpp

@@ -2454,7 +2454,7 @@ void NPC::ModifyNPCStat(std::string stat, std::string value)
 		stat_lower
 	);
 
-	SetEntityVariable(variable_key.c_str(), value.c_str());
+	SetEntityVariable(variable_key, value);
 
 	LogNPCScaling("NPC::ModifyNPCStat: Key [{}] Value [{}] ", variable_key, value);