Add navigation buttons (next and back) to announcements

Problem statement:

Currently, for instructors and students to review announcements in a course, they need to navigate to the Announcement Index page, click an announcement, read it, navigate back to the Index page, click the next announcement. Being able to click a Next or Back button to navigate between sequential announcements would improve the user experience and efficiency of navigating in Canvas.

Proposed solution:

Being able to click a Next or Back button to navigate between sequential announcements in the course would improve the user experience and efficiency of navigating in Canvas. For instructors, their Next and Back buttons would navigate all (posted and unposted) announcements in chronological order. Students' Next and Back buttons would only navigate between posted announcements.

User role(s):

instructor,student,ta