Scroll images in project issues separately from the remaining issue (go-gitea#31683)

As discussed in go-gitea#31667 & go-gitea#26561, when a card on a Project contains
images, they can overflow the card on its containing column. This aims
to fix this issue via snapping scrollbars.

---
Issue go-gitea#31667 is open to discussion as there should be room for
improvement.

Author: SimonPistache

web_src/css/features/projects.css

@@ -70,15 +70,20 @@
 .card-attachment-images {
   display: inline-block;
   white-space: nowrap;
-  overflow: hidden;
+  overflow: scroll;
+  cursor: default;
+  scroll-snap-type: x mandatory;
   text-align: center;
 }
 
 .card-attachment-images img {
   display: inline-block;
   max-height: 50px;
   border-radius: var(--border-radius);
+  text-align: left;
+  scroll-snap-align: center;
   margin-right: 2px;
+  aspect-ratio: 1;
 }
 
 .card-attachment-images img:only-child {

web_src/css/repo/issue-card.css

@@ -2,7 +2,7 @@
   display: flex;
   flex-direction: column;
   gap: 4px;
-  align-items: start;
+  align-items: stretch;
   border-radius: var(--border-radius);
   padding: 8px 10px;
   border: 1px solid var(--color-secondary);