Re-write metalbond server/client in rust

[guvenc]

Rust is a type safe language with a very strict compiler. Makes system level programming much safer. Therefore provide a PoC metalbond client and server in rust with the help of tokio framework.

• Try to avoid mutex usage and data structure locking.
• Try to reduce the number of threads used.
• Add also HA support.

Tasks:

• [x] Implement rust based PoC metalbond server.
• [ ] Implement rust based PoC metalbond client.
• [ ] Add HA support.
• [ ] Add unit tests/automated tests.
• [ ] Refactor.