Refactor several "field grids" per Buefy theme

e.g. the Users field when viewing a Role, and Vendor Sources panel
when viewing a Product

tailbone/templates/grids/b-table.mako

@@ -15,6 +15,9 @@
    % if loading is not Undefined and loading:
    :loading="${loading}"
    % endif
+   % if grid.default_sortkey:
+   :default-sort="['${grid.default_sortkey}', '${grid.default_sortdir}']"
+   % endif
    >
 
   <template slot-scope="props">
@@ -47,7 +50,11 @@
         <b-table-column field="actions" label="Actions">
           % for action in grid.main_actions:
               <a :href="props.row._action_url_${action.key}"
+                 % if action.link_class:
+                 class="${action.link_class}"
+                 % else:
                  class="grid-action${' has-text-danger' if action.key == 'delete' else ''}"
+                 % endif
                  % if action.click_handler:
                  @click.prevent="${action.click_handler}"
                  % endif