tart list: support -q (or --quiet) for automation purposes (#293)

Sources/tart/Commands/List.swift

@@ -5,9 +5,14 @@ import SwiftUI
 struct List: AsyncParsableCommand {
   static var configuration = CommandConfiguration(abstract: "List created VMs")
 
+  @Flag(name: [.short, .long], help: ArgumentHelp("Only display VM names"))
+  var quiet: Bool = false
+
   func run() async throws {
     do {
-      print("Source\tName")
+      if !quiet {
+        print("Source\tName")
+      }
 
       displayTable("local", try VMStorageLocal().list())
       displayTable("oci", try VMStorageOCI().list().map { (name, vmDir, _) in (name, vmDir) })
@@ -22,7 +27,11 @@ struct List: AsyncParsableCommand {
 
   private func displayTable(_ source: String, _ vms: [(String, VMDirectory)]) {
     for (name, _) in vms.sorted(by: { left, right in left.0 < right.0 }) {
-      print("\(source)\t\(name)")
+      if quiet {
+        print(name)
+      } else {
+        print("\(source)\t\(name)")
+      }
     }
   }
 }