replace anyhow and log with color_eyre and tracing

Since Himalaya is intended to be ran as a CLI in the terminal emulator
environment, their user experience could vastly improve with better and
more colorful error messages and logging.

This change will replace more minimal libraries for error-reporting/han-
dling with their more advanced counterparts.

Since these crates have tight integrations, this commit will change both
in one shot.

Also we have don't need env_logger any more. So I also have removed that
guy as well.

Signed-off-by: Perma Alesheikh <me@prma.dev>

src/backend/mod.rs

@@ -1,7 +1,7 @@
 pub mod config;
 pub(crate) mod wizard;
 
-use anyhow::Result;
+use color_eyre::Result;
 use async_trait::async_trait;
 use std::{ops::Deref, sync::Arc};
 

src/backend/wizard.rs

@@ -1,4 +1,4 @@
-use anyhow::Result;
+use color_eyre::Result;
 use dialoguer::Select;
 #[cfg(feature = "account-discovery")]
 use email::account::discover::config::AutoConfig;