api: support gRPC and provide SDKs

[zhenghaoz]

Compare to exited RESTful API, gRPC is more efficient for communications among servers.

Design

For each API, move current implementation to a shared handler, and call this shared handler from RESTful API handler as well as gRPC API handler.

┌───────────┐ ┌───────────┐
│RESTful API│ │ gRPC API  │
└─────────┬─┘ └─┬─────────┘
          │     │
        ┌─▼─────▼─┐
        │ Handler │
        └─────────┘

Tasks

• [ ] gRPC APIs
• [ ] Gorse Go SDK
• [ ] Gorse Java SDK
• [ ] Gorse Rust SDK
• [ ] Gorse Python SDK
• [ ] Gorse Node.js SDK

[bilinxing]

+1