SS3D's coder good practices

This is a draft to remind us we have to write this little guide.

• Avoid using Debug.Log, use Punpun logger instead. This is because we get much more relevant data using Punpun compared to Debug.Log.

• Use SystemLocator instead of the Find method from Unity when trying to get a reference. This is less prone to break and more efficient.

• To get an input, don't use Unity's built in methods, use instead our input system (put link there)