Add a test for donations with a white-label course mode
Merge pull request #5730 from edx/will/update-donation-tests

Add a test for donations with a white-label course mode
Migrate exercises and tools to shared folder
Merge pull request #5746 from edx/sylvia/docs/prob_migration

Migrate exercises and tools to shared folder
Replace index file
Merge pull request #5748 from edx/sylvia/docs/prob_correct

Replace index file