anyhow integration

[repi]

anyhow is a great, small and clean failure create replacement that was released very recently, would be great to have a sentry integration for it.
Probably can use the failure one as a base.

We are currently testing to transition from failure to anyhow to have a simpler library that implements std::error::Error

[Swatinem]

to anyhow to have a simpler library that implements std::error::Error

too bad anyhow does not actually implement std::error::Error. Would have been really straightforward otherwise.

This was implemented in #212 but I still have some cleaning up to do before I can cut a release.