feat: make scene optional in constructors

[Gugustinette]

Right now, Fibbo classes are taking the FScene as an explicit required parameter :

new FRectangle(scene, {...options})

The scene parameter could be part of the options and become optional.
By default, when creating a scene, it will be attached to a global object (globalThis) and used if no scene is provided in options.
If a scene parameter is provided through options, it will be used instead of the global one.

That way, components can be created as below :

new FRectangle({...options})