ECOM-1523

Extends the common capa response types (string, numeric, multiple
choice, checkbox, dropdown) with feedback and hint
capabilities. "Feedback" refers to feedback shown to the student when
they check the problem, looking at their specific answer. "Hints"
refers to a Hint button in LMS which the student can click at any time
to see hints for that problem. The implementation extends the markdown
syntax to include feedback and hints. There are new Feedback-and-Hint
specific templates in Studio when the author clicks to add a new
problem.

Before the leanModal content css was applied after the js class
was added to the body element. This causes leanModals to
display for a split second before being hidden. This fix removes
the need for the explicit css rule for static pages preview.

no need to create zero by in memory images

added contents to test upload files

TNL-2384

Refactored Studio's PagingView to use RequireJS Text and moved it
to common so that it can also be used by LMS.

PLAT-674

ECOM-1591

* Add end-point for initiating a request for credit from a provider.
* Add an end-point for a provider to update the status of a request (approved / denied).

TNL-2425

Also reconfigured paver to compile Sass into CSS directories

Fixed cms course export

TNL-2321

* Add Python API functions for creating and updating requests for credit.
* Add Django models and migrations for tracking credit requests and status.

Also moves the default icons to the badges subfolder to avoid storage conflicts.

TNL-2314

TNL2159