Add widget support to SourceColumn

Allow passing a widget class to SourceColumn. This makes
using lambdas to render model column unnecesary and are
mostly removed too.

Signed-off-by: Roberto Rosario <Roberto.Rosario@mayan-edms.com>

mayan/apps/user_management/views.py

@@ -55,7 +55,7 @@ class GroupListView(SingleObjectListView):
 
     def get_extra_context(self):
         return {
-            'hide_link': True,
+            'hide_object': True,
             'no_results_icon': icon_group_setup,
             'no_results_main_link': link_group_create.resolve(
                 context=RequestContext(request=self.request)
@@ -261,7 +261,7 @@ class UserListView(SingleObjectListView):
 
     def get_extra_context(self):
         return {
-            'hide_link': True,
+            'hide_object': True,
             'no_results_icon': icon_user_setup,
             'no_results_main_link': link_user_create.resolve(
                 context=RequestContext(request=self.request)