[Performance] Client / NPC Position Update Optimizations (#4602)

* Zone optimizations

* More changes

* More

* Update entity.cpp

* Beautiful

* Amazing

* Feature flag all logic

* Broadcast to group

* Update mob.cpp

* Updates

* Update client.cpp

* Update client.cpp

* Add rule Zone:EnableEntityClipping

* Little bit of cleanup

* Don't send update to self while in group

* Remove visibility work and feature flags

* Cleanup

* Logging

* Improve CheckSendBulkNpcPositions

* No need to cast

* Field cleanup

* Build initial list on zone-in

common/timer.h

@@ -86,6 +86,9 @@ struct BenchTimer
 	void reset() { start_time = clock::now(); }
 	// this is seconds
 	double elapsed() { return std::chrono::duration<double> (clock::now() - start_time).count(); }
+	std::chrono::milliseconds::rep elapsedMilliseconds() { return std::chrono::duration_cast<std::chrono::milliseconds>(clock::now() - start_time).count(); }
+	std::chrono::microseconds::rep elapsedMicroseconds() { return std::chrono::duration_cast<std::chrono::microseconds>(clock::now() - start_time).count(); }
+	std::chrono::nanoseconds::rep elapsedNanoseconds() { return std::chrono::duration_cast<std::chrono::nanoseconds>(clock::now() - start_time).count(); }
 private:
 	std::chrono::time_point<std::chrono::high_resolution_clock> start_time;
 };