@slidy/svelte: autoplay

[EricRovell]

Tha autoplay feature was requested frequently while slidy was at v2.x.

As I see it, the feature should be implemented using these interface:

• autoplay - indicating the state;
• interval value in ms;

Also, there are more to consider:

• Should the autoplay stop on hover or focus?
• Should the autoplay stop at the end of the carousel?

For accessibility there should be a pause button too.

[Valexr]

Hover & focus stop will good optioned & stop by edges if not loop mode i think

[EricRovell]

Implemented autoplay feature. Not much configurable yet, still it works to accordance to accessibility guidelines.