Transfer rocksdb-rs Repo to tikv org

Background

To evolve towards the next generation database engine kernel, we reimplemented RocksDB using rust. This is our project address: https://github.com/rust-lib-project/rocksdb-rs. Of course, we will not implement all the functions of RocksDB. Our purpose is to create a more general KV data engine for TiKV services, not a transactional data engine for MyRocks services. In this project, we will eliminate most of the features that TiKV in RocksDB does not use, including transactions and two-phase commit code, in order to simplify our code as much as possible and make the project easier to maintain.
For the cloud ecosystem, asynchronous IO is essential for high-latency cloud disks. Fortunately, rust provides an asynchronous framework that is easier to use than C++, allowing us to easily write asynchronous IO code. Therefore, most of the interfaces of this project are provided as asynchronous method. Thanks to all interfaces supporting asynchrony, we can merge the compaction thread pool with other background thread pools in tikv to reduce thread switching and control CPU resources more precisely.
At present, rocksdb-rs still maintains similar interface methods and functions as rocksdb, but it adopts a low-coupling architecture, which can be easily refactored into a more friendly interface for TiKV in the future.

Roadmap

At present, the project has implemented the basic functions of rocksdb, including read and write queries and background merging. But it still lacks a lot of tests, and some key functions (you can see more details in https://github.com/rust-lib-project/rocksdb-rs/issues), I hope he can get help from more developers under the tikv organization and play a bigger role.

Start by reviewing the rocksdb-rs project at https://github.com/rust-lib-project/rocksdb-rs and the related issues linked in the roadmap, then check the transfer requirements with the tikv organization. Done means the repository is transferred into the tikv organization and its project links and ownership are confirmed.