add remaining perms to new role, include update hook #2761

#### Changes

* move _cp_user_list_roles() to .module file, to be available during
update hook.
* Add "content editor" to remaining exported permissions in modules:
`os`, `os_comments`,`os_slideshow`,`os_wysiwyg`
* Add update hook to revert the necessary modules.
Merge pull request #3018 from openscholar/2761-more-perms

add remaining perms to new role, include update hook #2761