Add Newsletter service to support functionality for unfollowing newsletters
Add Newsletter REST controller and routing
Implement newsletter-related endpoints and methods in the User Service
Create UnfollowRequest for the INewsletterService interface
Add MyListNewsletterResponse to user's data fields
Add newsletter validation
Refactor JS components to support newsletter type and simplify recipient forms by moving logic to FormRecipient component
Refactor window global constants to support newsletters
Modify server to initialize and use the newsletter services
Add UI component for listing newsletters
Refactor existing components to use FormRecipient for recipient data input
* feat: manage participant
* refactor(group.go): change HTTP methods for managing group participants to use POST instead of DELETE and PATCH for better compatibility and consistency
* chore: update image homepage
Aldino Kemal