Add send extrinsic to substrate

[freddyli7]

SDK will need to send extrinsic to substrate
For Phala sygma pallet, extrinsic includes bridge request, retry

Implementation details

details could be found in the SoW research doc

Testing details

Unit test

Acceptance Criteria

SDK should have ability to send extrinsic to any substrate
SDK should be able to send bridge request extrinsic and retry extrinsic to Phala sygma pallet