Update collections crud rest api

[ChrisChV]

• Update description as optional: 3c79543
• Update create collection API to auto-generate key: 8118b77

[rpenido]

LGTM 👍
Thank you for your work, @ChrisChV!
I think it is missing the handler to update the search index after creating a collection. If you feel this should be done in another task, make sure that you create one for it (I didn't find any).

• I tested this using the instructions from openedx/frontend-app-authoring#1259
• I read through the code
• I checked for accessibility issues
• Includes documentation

[pomegranited]

👍 @ChrisChV Thank you for proposing this solution. I'm ok with this change -- since we added Collection.key late in the game, there's no explicit requirement to let users enter their own key, and we're under some time pressure here.

• I tested this on my tutor devstack with openedx/frontend-app-authoring#1260
• I read through the code
• I checked for accessibility issues N/A
• Includes documentation N/A
• User-facing strings are extracted for translation N/A

[pomegranited]

@rpenido

I think it is missing the handler to update the search index after creating a collection. If you feel this should be done in another task, make sure that you create one for it (I didn't find any).

I created this ticket for that: openedx/frontend-app-authoring#1260

Trying to get it done under FAL-3817, but will see.