Add simple template hook for "before object helpers"

not sure how useful, but needed in one place, and hook makes for
cleaner template inheritance

tailbone/templates/form.mako

@@ -34,6 +34,9 @@
     </div>
 
     <div style="display: flex; align-items: flex-start;">
+
+      ${before_object_helpers()}
+
       <div class="object-helpers">
         ${self.object_helpers()}
       </div>
@@ -46,6 +49,8 @@
   </div>
 </%def>
 
+<%def name="before_object_helpers()"></%def>
+
 <%def name="render_this_page_template()">
   % if form is not Underined:
       ${self.render_form()}