Responsive images update

⚠️ Extra Responsive Images classes changes ⚠️

.responsiveImagePlaceholder             >   .extra-responsive-image-wrapper
.responsiveBackgroundImagePlaceholder   >   .extra-responsive-image-background
.responsiveSvgImagePlaceholder          >   .extra-responsive-image-svg
.placeholder-canvas                     >   .extra-responsive-image-placeholder-canvas
.placeholder-image                      >   .extra-responsive-image-placeholder-thumb
.responsiveImageLazy                    >   .extra-responsive-image-lazy
.extra-custom-loading                   >   .extra-responsive-custom-loading

😎 Introducing extra sticky as permanent module

$('.exemple').extraSticky();

Available options at the moment :

'class'                 : 'sticky', // class added to the sitcked element
'container'             : null,     // add a specific container, or use the element parent by default
'limit'                 : true,     // limit the stick height, or unlimited stick in height
'offset'                : 0,        // offset the stick detection
'keepContainerHeight'   : false,    // maintain container height when element is sticked
'keepChildWidth'        : false     // maintain element width when sticked