Handle `loading` attribute as part of `lazy` field in image shortcode plugin

[Kapelianovych]

There might be a way to decide whether we can use the native loading attribute or a library for lazy loading. The same goes for the decoding attribute.

[Kapelianovych]

Workaround till the issue will be fixed:

this.image('url', { loading: 'eager', decoding: 'sync' })

You can rewrite loading and decoding attributes of the image by passing them explicitly to image options.