When a given user doesn't have the capability to "Include user data"
during course copying, freeze the form element rather than not adding
it at all.
This caused problems as the element was required before preceding with
the course copy.
This patch adds better core support for copying courses.
There is now a simplified and dedicated UI for copying
courses. This can be accessed from the course context
menu or course management screens.
All backups are done asynchronously and there can be multiple
copies of a course in flight at once.
Paul Holden