Add Poseidon strategy

[zhisbug]

System information

• AutoDist version:
• Are you willing to contribute it (Yes/No):

Describe the new feature and the current behavior/state

Will this change the current API? How?

Describe alternatives you've considered

Additional context
Poseidon uses a combination of parameter server, sufficient factor broadcasting to communicate messages whenever resulting in fewer communication overheads. We want a strategy implementation of it on top of AutoDist.