I have a lot of scars all over my body. Is there a surgery to replace the entire top layer of skin?

Sorry, no. Even if there were, it would not remove the scars as they are deeper than the top layer of skin. Pick the one or two you hate the most and show them to a plastic surgeon so he can advise you about ways to minimize their appearance and work from there.
No. Every injury to the skin, whether accidental or intentional, leaves a scar, even if it is performed by a plastic surgeon. There is no way to resurface your entire outer layer of skin. Scars that are significantly unsightly may be improved by surgical excision and careful closure.
Risk of scars. The risk of scarring is prohibitive therefore we prefer to use "resurfacing techniques" that remove a partial thickness and rely on the skin to heal itself. Deeper treatments have a greater risk of scars. Superficial imperfections can be removed whereas deeper ones will persist. Ablative & non ablative lasers, needling, chemicals or mechanical (deemabrasion) techniques are used.
No. No. This would be incredibly dangerous, and scars involve your deeper skin layers as well.
Yes. Its called a split thickness skin graft but would make it look worse. Scar revision surgery is an art which only abms/abps- certified(that is in my opinion- look for asps logo on web pg) surgeons are good at. I offer a discount for this in almost every self- pay case. It's no coincidence psych problems are often referred to as "mental scars". Scars have signif emotional effects and should be treat.
Find a dermatologist. I hear you trying to reach out to help you find a technique that can help with scars. When there are scars that embarrass you in highly visible areas like your face or arms, you can find a dermatologist that can work with you to find a non surgical option like dermabrasion. The top fayer of your skin can be "sanded" down and reheal to give you a smoother look, or sometimes topical medications.
No. There is not a procedure to remove the entire skin on your body. In certain cases, expanders can be used to stretch healthy skin to cover damaged skin.