feat: Add Learners list [BD-38] [TNL-8841] (#83)

Adds a new tab and listing view for learners in a course that have interacted with the discussions forums. It reports stats about the learner's created posts, comments, and reported content. 

Co-authored-by: Kshitij Sobti <kshitij@sobti.in>

src/data/constants.js

@@ -119,6 +119,11 @@ export const TopicOrdering = {
   BY_COMMENT_COUNT: 'sortByCommentCount',
 };
 
+export const LearnersOrdering = {
+  BY_FLAG: 'flagged',
+  BY_LAST_ACTIVITY: 'activity',
+};
+
 /**
  * Enum for discussion provider types supported by the MFE.
  * @type {{OPEN_EDX: string, LEGACY: string}}
@@ -134,6 +139,10 @@ export const Routes = {
   DISCUSSIONS: {
     PATH: BASE_PATH,
   },
+  LEARNERS: {
+    PATH: `${BASE_PATH}/learners`,
+    LEARNER: `${BASE_PATH}/learners/:learnerUsername`,
+  },
   POSTS: {
     PATH: `${BASE_PATH}/topics/:topicId`,
     MY_POSTS: `${BASE_PATH}/my-posts(/:postId)?`,
@@ -177,4 +186,5 @@ export const ALL_ROUTES = []
   .concat(Routes.COMMENTS.PATH)
   .concat(Routes.TOPICS.PATH)
   .concat([Routes.POSTS.ALL_POSTS, Routes.POSTS.MY_POSTS])
+  .concat([Routes.LEARNERS.LEARNER, Routes.LEARNERS.PATH])
   .concat([Routes.DISCUSSIONS.PATH]);