Rust Teller

[Varunram]

Rust is faster than golang and in some cases might be lighter as well. Speed is of importance to an application like the teller, which interacts with multiple parts in the opensolar ecosystem - the teller, IPFS and the Stellar blockchain. For this case, it might be useful to have a version of the Teller in Rust, so we c an compare performance and arrive at a simpler way of doing things.