Moved Studio images from img/ directory to images/ directory

OPEN-304
Add created_on and created_by to asset metadata storage.
https://openedx.atlassian.net/browse/PLAT-278
Fix the DJFS dependency.
Merge pull request #5953 from edx/jeskew/created_by_on_addition

Add created_on and created_by to asset metadata storage.
Merge pull request #5955 from edx/sanchez/fix-djfs-dependency

Fix the DJFS dependency.
Merge pull request #5941 from edx/studio-images

Moved Studio images from img/ directory to images/ directory
disable "go to payment button" on click (ECOM-643)
Merge pull request #5957 from edx/adam/disable-purchase-button-on-click

disable "go to payment button" on click (ECOM-643)