[Inbox] Add search feature for Inbox/Conversations

[stevenwilliams]

Finding a specific message in the Canvas Inbox is a difficult task due to the lack of a search feature. This is compounded for instructors of large courses, who may have thousands of students over the course of just a single academic year. 

This is not a new request, but all previous feature requests around this topic have been archived:

https://community.canvaslms.com/ideas/8587 

https://community.canvaslms.com/ideas/5105 

https://community.canvaslms.com/ideas/1359 

https://community.canvaslms.com/ideas/2828 

https://community.canvaslms.com/ideas/6106 

Because this issue has such a disproportionate impact on instructors of large courses -- who have a large number of inbox messages -- there may be some alignment between this ongoing need and the Instructure Priority: Teaching & Learning at Scale initiative.

[tragarz_roberta]

Yes!!! Please!!!!