[Cleanup] Gender constants cleanup (#3817)

* [Cleanup] Gender constants cleanup

# Notes
- Convert to a `Gender` namespace using `constexpr`.
- Cleanup spots where we were using magic numbers for gender values.

* Cleanup

zone/beacon.cpp

@@ -49,9 +49,9 @@ Beacon::Beacon(const glm::vec4 &in_pos, int lifetime) : Mob(
 	nullptr, // in_lastname
 	0, // in_cur_hp
 	0, // in_max_hp
-	MALE, // in_gender
-	INVISIBLE_MAN, // in_race
-	0, // in_class
+	Gender::Male, // in_gender
+	Race::InvisibleMan, // in_race
+	Class::None, // in_class
 	BT_NoTarget, // in_bodytype
 	0, // in_deity
 	0, // in_level