Saving tutorial only mentions JSON

**Your Godot version:**
4.0.1

**Issue description:**
The current tutorial on saving games only mentions JSON for serializing save data. I understand that generally, we want to discourage users from using JSON as opposed to Godot's built in resource serialization as JSON is less efficient and harder to work with in the engine.

It would be great to have an article discussing the pros and cons of different serialization methods, as well as a few common "gotchas" that people might run in to or perhaps an FAQ section. For instance, why should or shouldn't I save my whole game as one giant packed scene? What security issues should I be aware of when loading game data from custom resources? When I load my game and something breaks, what strategies can I use to debug the problem?

I'm willing to take the lead on writing these docs, but I will need help as I haven't actually made a fully fledged save system in Godot yet and I'm still a new contributor. If you'd like to help out, feel free to @nlupugla in Rocket chat.

**URL to the documentation page (if already existing):**
https://docs.godotengine.org/en/stable/tutorials/io/saving_games.html