feat: error reporting with eyre

[dangush]

Closes #134

The custom error type using thiserror that we had was not effective for handling errors in a descriptive manner.

I've learned now that the advice is to use anyhow/eyres for adding context to backtraces of errors when writing application logic, and using thiserror for custom error types when writing libraries.

So I removed our error.rs file and replaced all instances of Error with eyres::{Result, Report}.

I also modified the CwClient CLI impl to use eyres instead of anyhow for compatibility, and to throw errors when the underlying binary can't be found.

Example:

[hu55a1n1]

Awesome! 👏
Tested with common mistakes in all CLI commands and errors look more expressive. Pushed some cleanup and fixed a regression (not originating from this PR).