Feature request: Support native loading=lazy image attribute

It would be great to support the native lazy loading attribute at least for images.

We have a browser support of 74.96% at this time, only the new IE (Safari) doesn't support it in the current version. But it's already in the Technology Preview and should be in the next major update of MacOS and IOS.

Data based on https://caniuse.com/loading-lazy-attr

In addition I hope it's possible to make this work with also with the picture element.

Resources:
https://developer.mozilla.org/en-US/docs/Web/Performance/Lazy_loading
https://html.spec.whatwg.org/multipage/urls-and-fetching.html#lazy-loading-attributes

Start by reviewing the MDN lazy-loading documentation and the HTML specification linked in the issue, then locate Flickity's image and picture rendering path. The change is complete when native loading="lazy" support works for images and, if feasible, picture elements, with behavior verified in supported browsers.

Written by the indexing model from the issue text.