All the setup/teardown/pre/post/conditions template methods
now are required to return void. This was warned with phpunit 7
and now is enforced.
At the same time, fix a few wrong function names,
provider data and param types, return statements...
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.