tart delete: allow removing multiple VMs at once (#257)

Sources/tart/Commands/Delete.swift

@@ -6,11 +6,13 @@ struct Delete: AsyncParsableCommand {
   static var configuration = CommandConfiguration(abstract: "Delete a VM")
 
   @Argument(help: "VM name")
-  var name: String
+  var name: [String]
 
   func run() async throws {
     do {
-      try VMStorageHelper.delete(name)
+      for it in name {
+        try VMStorageHelper.delete(it)
+      }
 
       Foundation.exit(0)
     } catch {