Use raft state to maintain membership state and hashing table in placement

[youngbupark]

In what area(s)?

/area placement

Describe the feature

This is the part of #663

This switches in-memory dapr runtime host membership and hashing table to the state maintained by Raft. All the missing unit-tests need to be added.

Release Note

RELEASE NOTE: USE Raft state to maintain dapr runtime host state and hashing table