Implement AIP18

[faustbrian]

https://github.com/ArkEcosystem/AIPs/blob/master/AIPS/aip-18.md

See https://github.com/ArkEcosystem/core/tree/master/packages/crypto/src for reference once Core 2.6 is released.

[stale]

This issue has been automatically marked as stale because it has not had recent activity. It will be closed if no further activity occurs. Thank you for your contributions.

[faustbrian]

This currently is waiting for Bit-Wasp/bitcoin-php#758 to be merged.