* feat: 🎉 Image component

* fix color

* fix style naming and sort api doc order

* remove onPreviewClose doc

* use animation-duration var

* use box and modal-mask mixins

* use box and modal-mask mixins

* improve style

* improve fallback demo src

* add cover

* improve demo

* update demo snapshots

* upgrade rc-image, naming Random -> Reload

* extract modal mask common style, and improve demo

* update snapshots

* fix less var conflict

* upgrade rc-image, adjust maxSize with dark.min.css, improve placeholder demo desc