Implement the http variant of the bank server.

During that process, many shortcomings with the socket server and the
bank lib were fixed.

I am aware a massive commit like this is not ideal.

socket-server/src/commands/error.rs

@@ -0,0 +1,35 @@
+use std::fmt::{Display, Formatter};
+use std::ops::Deref;
+
+use thiserror::Error;
+
+use bank::account::AccountError;
+
+#[derive(Debug, Error)]
+pub struct SocketAccountError(pub AccountError);
+
+impl Display for SocketAccountError {
+    fn fmt(&self, f: &mut Formatter<'_>) -> std::fmt::Result {
+        write!(f, "{}", self.deref())
+    }
+}
+
+impl Deref for SocketAccountError {
+    type Target = AccountError;
+
+    fn deref(&self) -> &Self::Target {
+        &self.0
+    }
+}
+
+impl From<SocketAccountError> for u8 {
+    fn from(e: SocketAccountError) -> Self {
+        match e.deref() {
+            AccountError::Overdraw => 11,
+            AccountError::Inactive => 12,
+            AccountError::InvalidAmount => 13,
+            AccountError::NotFound => 14,
+            AccountError::AccountNotZero => 15,
+        }
+    }
+}