Replace failure crate with std::error::Error

[tjanez]

SUMMARY

As the standard library has been fixing the Error trait recently (tracking issue: rust-lang/rust#53487, RFC: https://github.com/rust-lang/rfcs/blob/master/text/2504-fix-error.md), there is less and less need to use the failure create.

Coupled with failure crate's instabilities (rust-lang-deprecated/failure#342 being the most recent), people have been recommending its replacement, for example:

• Remove failure dependancy and favor std::error::Error rust-cli/confy#23
• https://users.rust-lang.org/t/failure-derive-compilation-error/39062/14

ISSUE TYPE

• Feature Idea

ADDITIONAL INFORMATION

• Rust Error Handling Survey by Yoshua Wuyts (Nov 13, 2019)