DISCUSS: merge eyre and anyhow libraries

[ten3roberts]

Eyre is a close clone of anyhow which aims to provide extra configurabilities and more dynamic features compared to anyhow.

The library has been able to achieve its purpose and provide more elaborate error handling.

However, there has been compatibility issues and fragmentation arising when mixing the use of the libraries, most often due to external crates or ecosystem conventions. It is not easy to mix the usage of convert between anyhow::Error and eyre::Report and preserve the backtrace and other data.

Numerous attempts, issues and discussions have been related to this topic

#31
#171
Backtrace preserving conversion PR

The discussed solution has been to rethink our approach and reconcile the two libarier, providing a hook similar to the log crate in anyhow, and making eyre and most notably color-eyre integrate with anyhow directly, allowing the community to use both libraries together rather than fighting the chasm.

Any feedback is more than welcome

[joshtriplett]

Discussion and plans in this regard may also want to consider the possibility of getting a subset of eyre's functionality merged into the standard library.