Performance/inbox paging (#11258)

* merge all changes to one commit of PR #11157 / #11226

* rename the new paged messages route

* rename event, move map-method to the Inbox schema, fix lint

* move `mapMessage`-call to `getUserInbox`

* revert schema.method back to a normal one

website/client/components/chat/chatCard.vue

@@ -273,5 +273,8 @@ export default {
       return habiticaMarkdown.render(String(text));
     },
   },
+  mounted () {
+    this.$emit('chat-card-mounted', this.msg.id);
+  },
 };
 </script>