For action which require a confirmation message.
This is a way to have a template for every confirmation message in the
app.
Example of usage :
```
{{ include('ChillMainBundle:Util:confirmation_template.html.twig',
{
# a title, not mandatory
'title' : 'Remove membership'|trans,
# a confirmation question, not mandatory
'confirm_question' : 'Are you sure you want to remove
membership of "%name%" from the group "%group%"?'|trans({ '%name%' :
person.firstname ~ ' ' ~ person.lastname, '%group%' :
membership.cgroup.name }),
# a route for "cancel" button (mandatory)
'cancel_route' : 'chill_group_membership_by_person',
# the parameters for 'cancel' route (default to {} )
'cancel_parameters' : { 'person_id' : membership.person.id
},
# the form which will send the deletion. This form
# **must** contains a SubmitType
'form' : form
} ) }}
```
