feat: update wallet::Balance to use bitcoin::Amount

- update all fields `immature`, ` trusted_pending`, `unstrusted_pending`
  and `confirmed` to use the `bitcoin::Amount` instead of `u64`
- update all `impl Balance` methods to use `bitcoin::Amount`
- update all tests that relies on `keychain::Balance`

example-crates/example_cli/src/lib.rs

@@ -506,11 +506,11 @@ where
             let chain = &*chain.lock().unwrap();
             fn print_balances<'a>(
                 title_str: &'a str,
-                items: impl IntoIterator<Item = (&'a str, u64)>,
+                items: impl IntoIterator<Item = (&'a str, Amount)>,
             ) {
                 println!("{}:", title_str);
                 for (name, amount) in items.into_iter() {
-                    println!("    {:<10} {:>12} sats", name, amount)
+                    println!("    {:<10} {:>12} sats", name, amount.to_sat())
                 }
             }