s2s bridge message delivery should return remote call execution result

[hackfisher]

In current s2s design, the source chain can only tell from the delivery proof that the message has already been delivered, but do not support to tell the execution result of remote call.

Message protocol level should provide application level with support for the ability to implement transactional business logic, by providing the execution status in the delivery.

Current parity bridge common implementation does not support this, we need to do enhancement to achieve this.

Similar requirement also apply to substrate to evm-family bridge's message channel.

Refer

https://github.com/darwinia-network/darwinia-bridge-sol/blob/6b4e2895260e675578ba7ce51a0ac98c2f151340/contracts/bridge/contracts/BasicInboundChannel.sol#L97

darwinia-network/darwinia-messages-sol#41 (comment)

[hackfisher]

Supported by paritytech/parity-bridges-common#935

and ongoing application level support in #789]