Managed friend list for messenger (chat) - D8

The Drupal 8. Create a managed friend list for a messenger. The ability to send a request to add to friends from certain pages of the site, accept/reject the request, block the user (send to the "black list"), add to the selected ( remember the user without sending him a request to add to friends). Develop an interactive user alert system when performing actions on the site (JavaScript is used by bootstrap-notify library).