Add 'warning' class for 'delete' action in b-table grid

tailbone/templates/grids/b-table.mako

@@ -47,6 +47,7 @@
         <b-table-column field="actions" label="Actions">
           % for action in grid.main_actions:
               <a :href="props.row._action_url_${action.key}"
+                 class="grid-action${' has-text-danger' if action.key == 'delete' else ''}"
                  % if action.click_handler:
                  @click.prevent="${action.click_handler}"
                  % endif