Add user blocking

- Add the ability to block a user via their profile page.
- This will unstar their repositories and visa versa.
- Blocked users cannot create issues or pull requests on your the doer's repositories (mind that this is not the case for organizations).
- Blocked users cannot comment on the doer's opened issues or pull requests.
- Blocked users cannot add reactions to doer's comments.
- Blocked users cannot cause a notification trough mentioning the doer.

Reviewed-on: https://codeberg.org/forgejo/forgejo/pulls/540

models/activities/notification.go

@@ -235,6 +235,15 @@ func createOrUpdateIssueNotifications(ctx context.Context, issueID, commentID, n
 		for _, id := range issueUnWatches {
 			toNotify.Remove(id)
 		}
+
+		// Remove users who have the notification author blocked.
+		blockedAuthorIDs, err := user_model.ListBlockedByUsersID(ctx, notificationAuthorID)
+		if err != nil {
+			return err
+		}
+		for _, id := range blockedAuthorIDs {
+			toNotify.Remove(id)
+		}
 	}
 
 	err = issue.LoadRepo(ctx)