Move all source files to Sources/ and rename WireGuardKit targets

Signed-off-by: Andrej Mihajlov <and@mullvad.net>

Sources/WireGuardApp/UI/macOS/Application.swift

@@ -0,0 +1,19 @@
+// SPDX-License-Identifier: MIT
+// Copyright © 2018-2019 WireGuard LLC. All Rights Reserved.
+
+import Cocoa
+
+class Application: NSApplication {
+
+    private var appDelegate: AppDelegate? //swiftlint:disable:this weak_delegate
+
+    override init() {
+        super.init()
+        appDelegate = AppDelegate() // Keep a strong reference to the app delegate
+        delegate = appDelegate // Set delegate before app.run() gets called in NSApplicationMain()
+    }
+
+    required init?(coder: NSCoder) {
+        fatalError("init(coder:) has not been implemented")
+    }
+}