Replace error-chain by thiserror

[PaulGrandperrin]

Because of this issue in error-chain rust-lang-deprecated/error-chain#240 , errors from this crate are impossible to propagate when the user is using failures or anyhow and maybe others.

More info can be found here:

• support wrapping error_chain Error's ? / document that Send+Sync are required on top of std::error::Error dtolnay/anyhow#72
• Support converting error-chain into Failure::Error rust-lang-deprecated/failure#284

Moreover error-chain is not maintained anymore and the fix has, and will never be merged: rust-lang-deprecated/error-chain#241

thiserror is the recommend crate to generate errors from libraries: https://nick.groenen.me/posts/rust-error-handling/