I have an iMac and I also happen to have a MacBook Air. What I need is this strange layout - I want to be able to control my iMac with my MacBook. I also want to be able to share my iMaс screen to my MacBook's. So ideally I have a single machine - iMac responsible for all the hardware and the MacBook as just as an external display and a keyboard with a touchpad. How do you achieve this?