Wannabeadmin: Add "accept" and "deny" buttons on view

[hultberg]

When viewing application, allow admins to accept or deny an application. Only admin of a group can deny/accept a application. When accepting an application there should be a select of which group to add the user to and what access.

[Laaknor]

Should also send email to the user about being accepted or denied.

[hultberg]

@Laaknor A feature that would need to be implemented with this a template for accept and deny, and I would like the ability to choose if one want to notify the applicant about the change. Since we have twig in lancms1 already, we can allow administrators to provide a full fledge template via wannabeadmin. We can exploit the following variables as a start: username, name, date.

Read more about twig templates here: http://twig.sensiolabs.org/doc/2.x/