CLONE - A plugins check page is provided for administrators when upgrading

This test requires access to a local test site which can be upgraded.

1. Edit /mod/workshop/version.php and increase the $module->version to stimulate upgrade.
2. Rename /mod/chat to /mod/.chat to simulate a module missing from disk.
3. Go to your /mod folder and run `git clone https://github.com/skodak/moodle-mod_book.git book` to have a new module available.
4. Login as admin and go to your /admin page.
5. Click on the 'Display the full list of installed plugins link for all available plugins.
6. Check that the status of the Workshop module is 'upgrade needed'.
7. Check that the status of the Book module and its submodules is 'to be installed'.
8. Check that the status of the Chat module is 'missing from disk'.