Optional r: numberdefines the red component (between 0 and 1, default is 0)
Optional g: numberdefines the green component (between 0 and 1, default is 0)
Optional b: numberdefines the blue component (between 0 and 1, default is 0)
Optional a: numberdefines the alpha component (between 0 and 1, default is 1)
Creates create mutable Color4 from red, green, blue values, all between 0 and 1