New right menu features and attachment manager

1. Attachment media manager.

Add attachment manager. Its purpose is to provide content sorting. Images, videos, links and files.

It is much easier to search and more interactive. Also these thumbnail images take up less space. This manager is in the right menu, similar to search. Menu size as a search.

2. Attached messages and mentions move to the right menu

Currently attached posts and mentions use a drop down menu. It is small and not so convenient. Transfer them to the right menu. Similar to search and manager attached.