Add UpdateCheck and some supporting code

Sources/AppUpdater/Support/Log.swift

@@ -0,0 +1,16 @@
+//
+//  Created by Nico Verbruggen on 30/05/2024.
+//  Copyright © 2024 Nico Verbruggen. All rights reserved.
+//
+
+import Foundation
+
+open class Log {
+    public static func text(_ text: String) {
+        self.handler(text)
+    }
+
+    public static var handler: (_ text: String) -> Void = { text in 
+        print(text)
+    }
+}