Paginate ancestor statuses in public page (#7102)

This also limits the statuses returned by API, but pagination is not
implemented in Web API yet. I still expect it brings user experience
better than making a user wait to fetch all ancestor statuses and flooding
the column with them.

app/javascript/styles/mastodon/stream_entries.scss

@@ -6,7 +6,8 @@
     background: $simple-background-color;
 
     .detailed-status.light,
-    .status.light {
+    .status.light,
+    .more.light {
       border-bottom: 1px solid $ui-secondary-color;
       animation: none;
     }
@@ -290,6 +291,17 @@
       text-decoration: underline;
     }
   }
+
+  .more {
+    color: $classic-primary-color;
+    display: block;
+    padding: 14px;
+    text-align: center;
+
+    &:not(:hover) {
+      text-decoration: none;
+    }
+  }
 }
 
 .embed {