Replace error-chain crate #24
Description
We use in many places error types created with error-chain (https://github.com/rust-lang-deprecated/error-chain). This library has been finally deprecated a few weeks ago, we should try to move away from it. I propose we use https://crates.io/crates/thiserror as it is most commonly the sanest choice when considering implementation effort and readability of produced error types. Also, from other projects I can report that its nice to maintain when long-term support is the goal.