Introduce "tart fqn" command (#735)

* tart pull: experimental --json-digest option

* Introduce "tart fqn" command

* Revert "tart pull: experimental --json-digest option"

This reverts commit 842052f5bd.

Sources/tart/Commands/FQN.swift

@@ -0,0 +1,22 @@
+import ArgumentParser
+import Foundation
+import SystemConfiguration
+
+struct FQN: AsyncParsableCommand {
+  static var configuration = CommandConfiguration(abstract: "Get a fully-qualified VM name", shouldDisplay: false)
+
+  @Argument(help: "VM name")
+  var name: String
+
+  func run() async throws {
+    if var remoteName = try? RemoteName(name) {
+      let digest = try VMStorageOCI().digest(remoteName)
+
+      remoteName.reference = Reference(digest: digest)
+
+      print(remoteName)
+    } else {
+      print(name)
+    }
+  }
+}

Sources/tart/Root.swift

@@ -26,6 +26,7 @@ struct Root: AsyncParsableCommand {
       Rename.self,
       Stop.self,
       Delete.self,
+      FQN.self,
     ])
 
   public static func main() async throws {