The course import now makes use of the backup and restore processed and the backup UI to allow the user to import one course into another.
The new UI is much the same as the backup ui except preceeded by a course selector to choose the course to import from.
* Category + course selectors now perform required capability checks
* Show/Hide settings from UI tested and implemented for overwrite_conf setting
* Final continue button is GET rather than post
* Temp zip file is deleted after successfull extraction
* Removed previous button from settings stage MDL-23480