[Dynamic Zones] Implement dz switch id (#2343)

This adds the `dz_switch_id` field to doors and dynamic_zones. It will
allow for compasses to be automatically added to dz entrances and will
support moving clients to the dz on use without needing to script it.
These can be imported for switches/doors from live packet dumps.

Also removes compass packet encoders (same struct in all clients)

zone/doors.h

@@ -25,6 +25,7 @@ public:
 	char *GetDoorName() { return door_name; }
 	const glm::vec4 GetDestination() const { return m_Destination; }
 	const glm::vec4 &GetPosition() const { return m_Position; }
+	int GetDzSwitchID() const { return m_dz_switch_id; }
 	int GetIncline() { return incline; }
 	int GetInvertState() { return invert_state; }
 	uint8 GetDoorID() { return door_id; }
@@ -91,6 +92,7 @@ private:
 	int       destination_instance_id;
 	glm::vec4 m_Destination;
 	uint8     is_ldon_door;
+	int       m_dz_switch_id = 0;
 	uint32    client_version_mask;
 };
 #endif