feat: add animation duration option

[zvandermeer]

Adds an optional animationDuration property to the createSwapy() method. If animationDuration is specified, the default animation duration will be overridden with the user-specified value. If animationDuration is not specified, the animation defaults to the duration set by the getAnimateConfig() method.

Example usage

createSwapy(container, {
  animationDuration: 180 // Set swap animation duration to 180ms
})

[zvandermeer]

Additionally, is there a repo for the swapy.tahazsh.com documentation website? I would be happy to update the documentation for this change if it is merged.