Add a Tag Display to Anonymous Posts [front-end]

[J0nathanLai]

Indicate the post is anonymous to instructors.

Estimated effort for each task: Medium
Dependencies among tasks: permissions and anonymous post button
Milestones to indicate which sprint the issue should be completed in (Sprint 1, Sprint 2, Stretch): Sprint 2
Acceptance criteria that describes how you know this task is done: Test on whether an anonymous post tag shows up on the instructors' screen after a student posts an anonymous post.

[kmehta5]

Completed adding a tag on posts, need to resolve dependency of adding back end logic.
Changes committed to "anonymous-tag" branch of front-end reop (no changes on main repo).