Load RT size only on demand to speed up configuration page load

For big RT instances, it takes time to calculate RT sizes and could
cause timeout. This commit makes the calculation part optional so admins
can still access Configuration page to check other info in that case.

share/html/Admin/Tools/Configuration.html

@@ -127,11 +127,12 @@
     </&>
 
     <&|/Widgets/TitleBox, title => loc("RT Size") &>
+
+%   if ( $LoadSize ) {
       <div class="form-row">
         <div class="collection-as-table label col-6 text-left"><&|/l&>Object</&></div>
         <div class="collection-as-table label col-6 text-left"><&|/l&>Size</&></div>
       </div>
-
 <%PERL>
 my ($index_size, $user_count, $privileged_count);
 for my $type (qw/Tickets Queues Transactions Articles Assets Groups PrivilegedUsers UnprivilegedUsers/) {
@@ -157,7 +158,11 @@
         <div class="collection-as-table value col-6"><% $count %></div>
       </div>
 % }
-    </&>
+
+%   } else {
+    <a class="mt-2 button btn btn-primary" href="?LoadSize=1"><&|/l&>Load Size</&></a>
+%   }
+</&>
 
   </div>
 
@@ -390,3 +395,7 @@
     return $output;
 }
 </%INIT>
+
+<%ARGS>
+$LoadSize => undef
+</%ARGS>