feat(hwi): add address subcommand for hwi

Author: tvpeter

src/commands.rs

@@ -478,6 +478,8 @@ pub enum HwiSubCommand {
     Devices,
     /// Register hardware wallet
     Register,
+    /// Generate address
+    Address,
 }
 
 /// Subcommands available in REPL mode.

src/handlers.rs

@@ -631,6 +631,10 @@ pub async fn handle_offline_wallet_subcommand(
                 //TODO: return status of wallet registration
                 Ok(json!({ "hmac": hmac }))
             }
+            HwiSubCommand::Address => {
+                let address = wallet.next_unused_address(KeychainKind::External);
+                Ok(json!({ "address": address.address }))
+            }
         },
     }
 }