Added delete a user service ,Added remove icon and refresh the user list

This `delete` function should not belong to `ModifyUserDetailsUseCase`. By design use cases are single-purpose objects. This one is __modifying__ user details, not removing user. `delete` should have its own use case class with its own validation (if any etc.). I know it may look like overkill, but it helps keeping things consistent and easy to reason about. 
Now it's like: "oh I see, this use case modifies user (adds admin rights etc), but why the hell it also removes one?"