Disable autosubscribe

As a User I'd like to be able to disable autosubscribing so that I don't get flooded with a lot of mails if I'm active writer

Acceptance Criteria:

• A checkbox 'Auto-subscribe is enabled' should appear on profile page
• When it's checked, user is subscribed to the topic she is posting to or to the own topic she is creating. If not checked, then user is not automatically subscribed to the topic.
• If I'm looking at my profile and I have EDIT_OWN_PROFILE, then checkbox is visible both on view and edit pages
• If I'm a guy with EDIT_OTHERS_PROFILE permission granted, I also should see the checkbox both on view and edit pages
• If I'm looking at someone's profile and I don't have EDIT_OTHERS_PROFILE permission set, I don't see checkbox on the view page (the same as Language)