Solution for [ENG-4560](https://linear.app/comm/issue/ENG-4560/bold-mentions-when-user-has-access-to-given-chat) and [ENG-4561](https://linear.app/comm/issue/ENG-4561/redirect-to-given-chat-when-mention-is-clicked).
This diff creates new component for chat mentions which handles bolding mentions when user has access to given chat and onPress events.