Issue #3491252 by alorenc, claudiu.cristea: Refactor inbox_block_script library

css/private_message_slide.css

css/private_message_slide.scss

js/private_message_inbox_block.js

js/private_message_inbox_previous.js

js/private_message_notification_block.js

js/private_message_slide.js

js/private_message_thread.js

js/private_message_utils.js

private_message.libraries.yml

tests/src/FunctionalJavascript/InboxBlockTest.php