[Web] Make 2048b key default

Signed-off-by: andryyy <andre.peters@debinux.de>

data/web/templates/modals/mailbox.twig

@@ -165,7 +165,7 @@
             <div class="col-sm-10">
               <select data-style="btn btn-default btn-sm" class="form-control" id="key_size" name="key_size">
                 <option data-subtext="bits">1024</option>
-                <option data-subtext="bits">2048</option>
+                <option data-subtext="bits" selected>2048</option>
               </select>
             </div>
           </div>
@@ -390,7 +390,7 @@
             <div class="col-sm-10">
               <select data-style="btn btn-default btn-sm" class="form-control" id="key_size2" name="key_size">
                 <option data-subtext="bits">1024</option>
-                <option data-subtext="bits">2048</option>
+                <option data-subtext="bits" selected>2048</option>
               </select>
             </div>
           </div>