Integrate Perfetto with Godot-CPP

[kisg]

This change adds an example on how to integrate Perfetto with Godot-CPP projects.

This PR is not yet suited for merging, it is just provided to provide an idea on how to use Perfetto integrated with Godot in GDNative projects.

Companion proposal: https://github.com/godotengine/godot-proposals/issues/5346

[MGilleronFJ]

Why does this have to be built into the bindings library's SConstruct? There doesn't seem to be a technical requirement for it (neither is the job of the bindings library to do so). I'm not familiar with this profiler, but I don't see a reason why projects using Perfetto wouldn't just put those few lines it in their build script instead (I use Tracy and don't need to do that either to use it).

If it's for the example, it could all be in the test project SConstruct. Although I wonder if it's a good idea over time to keep putting many examples of many libraries in the same project... just saying that for the concern of keeping it simple.