Implement container reordering

src/css/popup.css

@@ -691,6 +691,10 @@ h3.title {
   max-inline-size: 300px;
 }
 
+.menu-item.drag-over td {
+  border-block-start: 2px solid var(--text-normal-color);
+}
+
 .disabled-menu-item {
   color: grey;
   cursor: default;
@@ -932,6 +936,22 @@ tr:hover > td > .trash-button {
   display: block;
 }
 
+.move-button {
+  cursor: move;
+  display: inline-block;
+  height: 100%;
+  inline-size: 16px;
+  margin-block-end: 4px;
+  margin-block-start: 4px;
+  margin-inline-end: 10px;
+  margin-inline-start: auto;
+  text-align: center;
+}
+
+.move-button > img {
+  height: 16px;
+}
+
 @media (prefers-color-scheme: dark) {
   :root {
     --title-text-color: #fff;