tweak(ext/cfx-ui): require a minimum play time for reviews

This hot-fixes a common end-user request involving 'sockpuppet accounts'
being used to post negative reviews about servers.

Notable shortcomings of this hotfix:

  1. It is only implemented client-side, and if a server-side check is
     added, it must be kept in sync with the counter here.

     A server-side configuration service would help here.

  2. It does not indicate *why* the review form is disabled, that is,
     for a user which does not qualify to submit a review, the form will
     simply not show at all.

ext/cfx-ui/src/cfx/apps/mpMenu/services/servers/reviews/DiscourseServerReviews.ts

@@ -13,6 +13,10 @@ import { DiscourseServerReviewItem, IUserStub, RecognizedTopicTags } from "./rev
 // discourse' server reviews category id
 const REVIEWS_CATEGORY_ID = 76;
 
+// the required play time (in seconds) to be allowed to post a review
+const HOURS = 3600;
+const REVIEW_REQUIRED_PLAYTIME = (2 * HOURS);
+
 enum OwnReviewState {
   Loading,
   LoadingError,
@@ -63,6 +67,10 @@ export class DiscourseServerReviews implements IServerReviews {
       return false;
     }
 
+    if (!this.ownPlaytime || this.ownPlaytime.seconds < REVIEW_REQUIRED_PLAYTIME) {
+      return false;
+    }
+
     switch (this.ownReviewState) {
       case OwnReviewState.Exists:
       case OwnReviewState.Loading: