[FEATURE REQUEST] Scene.toJson()

[RuggeroVisintin]

Is your feature request related to a problem? Please describe.
Scenes can be loaded from JSON or a file path, but there is no way to get the JSON structure of the scene if anything is changed

Describe the experience you'd like
Having a .toJSON method on the scene would allow to get the JSON structure of the scene for further processing (for example serialization in a file)

Describe alternatives you've considered
N/A

Additional context
N/A

• implement .toJson() method in every component - #352
• implement .toJson() method in every entity - #367
• implement .toJson() method at the scene level - #368