Convert all "import" pages to use filepicker

All the pages where we have a simple"upload" to get import files should now use a filepicker:

Please add any others to this list:

• Grade import (see also MDL-22573)
• Glossary import
• Questions import
• Bulk student upload in admin
• Database entries import
• Outcomes import
• Course import (http://docs.moodle.org/en/Community_hub#Import_course)