contracts: Don't rely on reserved balances keeping an account alive (#13369)

* Move storage deposits to their own account

* Take ed for contract's account from origin

* Apply suggestions from code review

Co-authored-by: Cyrill Leutwiler <bigcyrill@hotmail.com>
Co-authored-by: Sasha Gryaznov <hi@agryaznov.com>

* Update stale docs

* Use 16 bytes prefix for address derivation

* Update frame/contracts/src/address.rs

Co-authored-by: Cyrill Leutwiler <bigcyrill@hotmail.com>

* Fix merge

* ".git/.scripts/commands/bench/bench.sh" pallet dev pallet_contracts

* Update frame/contracts/primitives/src/lib.rs

Co-authored-by: Sasha Gryaznov <hi@agryaznov.com>

---------

Co-authored-by: Cyrill Leutwiler <bigcyrill@hotmail.com>
Co-authored-by: Sasha Gryaznov <hi@agryaznov.com>
Co-authored-by: command-bot <>

substrate/frame/contracts/fixtures/drain.wat

@@ -34,8 +34,7 @@
 		)
 
 		;; Try to self-destruct by sending full balance to the 0 address.
-		;; All the *free* balance will be send away, which is a valid thing to do
-		;; because the storage deposits will keep the account alive.
+		;; The call will fail because a contract transfer has a keep alive requirement
 		(call $assert
 			(i32.eq
 				(call $seal_transfer
@@ -44,7 +43,7 @@
 					(i32.const 0)	;; Pointer to the buffer with value to transfer
 					(i32.const 8)	;; Length of the buffer with value to transfer
 				)
-				(i32.const 0) ;; ReturnCode::Success
+				(i32.const 5) ;; ReturnCode::TransferFailed
 			)
 		)
 	)