New Users: openraft, rust raft with improvements

[Xuanwo]

https://github.com/datafuselabs/openraft

Raft is not yet good enough. This project intends to improve raft as the next-generation consensus protocol for distributed data storage systems (SQL, NoSQL, KV, Streaming, Graph ... or maybe something more exotic).

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We added an openraft example to store snapshots on remote storage services via opendal.