Add a project setting to automatically add Editor's WorldEnvironment, DirectionalLight3D, and/or Camera3D to a 3D scene when running project with Run Current Scene/Run Specific Scene

[jaydensipe]

Closes godotengine/godot-proposals#6735
Closes godotengine/godot-proposals#5801
Closes godotengine/godot-proposals#5800
Closes godotengine/godot-proposals#10144 (maybe)
Closes godotengine/godot-proposals#7992 (maybe)
Fixes #95804

This commit adds a Project Setting (ENABLED BY DEFAULT) that when running the project with Run Current Scene or Run Specific Scene, adds the preview WorldEnvironment, DirectionalLight3D and/or Camera3D nodes from the Editor into the running game. This will NOT add any preview nodes if they already exist in the scene tree before running. This does NOT affect running a game normally.

I tried to adapt this the best I could to the discussion in godotengine/godot-proposals#5800, but am up to modify it in any way I should.

Some notes:

1. Code wise, I couldn't find a better way to pass the nodes through the debugger message than (var_to_bytes_with_objects) but chances are I missed something, is there a better way to do this?
2. Would we want to update this to update when the Environment/Sun preview button is toggled, as it stands right now it is only read when the game is started.

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Before	After
Screen.Recording.2024-10-18.214654.mp4	Screen.Recording.2024-10-18.214034.mp4