Add some a11y to the mix

src/organisms/Carousel.svelte

@@ -172,6 +172,9 @@
                     class:is-active={id === currentPhoto.id}
                     class:is-next={id === nextPhoto.id}
                     on:click={openFullscreen}
+                    role="group"
+                    aria-roledescription="slide"
+                    aria-label="Photo {index + 1} of {photos.length}"
                 >
                     <picture class="gallery__picture">
                         <source media="(min-width: 968px)" data-srcset={getThumbnail(image.private_hash, 1200)}>