Sort archive messages by date (and only then by id)

fix #3337

Because apparently the IDs are not always incrementing. We still use them to
know the order of two messages that were received at the same second (in
this case, the ID will always be incrementing).

src/database/database.cpp

@@ -197,11 +197,10 @@ std::vector<Database::MucLogLine> Database::get_muc_logs(const std::string& owne
       request << reference_record_id;
     }
 
-  request.order_by() << Id{};
   if (paging == Database::Paging::first)
-    request << " ASC ";
+    request.order_by() << Database::Date{} << " ASC, " << Id{} << " ASC ";
   else
-    request << " DESC ";
+    request.order_by() << Database::Date{} << " DESC, " << Id{} << " DESC ";
 
   if (limit >= 0)
     request.limit() << limit;