As a gRPC consumer, I want the CLI to collects all the files composing a sketch

[kittaakos]

It is already implemented by the CLI but it's not yet exposed as an API/command:

arduino-cli/arduino/builder/sketch.go

Lines 100 to 103 in fff99af

	// SketchLoad collects all the files composing a sketch.
	// The parameter `sketchPath` holds a path pointing to a single sketch file or a sketch folder,
	// the path must be absolute.
	func SketchLoad(sketchPath, buildPath string) (*sketch.Sketch, error) {

I would like to avoid duplicating code in the Pro IDE and fully rely on this CLI functionality.

Thank you!