Rewrite Logger

This reverts all of Roop's changes to the C code, and then rewrites the
logger logic to be cleaner.

Signed-off-by: Jason A. Donenfeld <Jason@zx2c4.com>

WireGuard/WireGuard/UI/iOS/AppDelegate.swift

@@ -12,17 +12,7 @@ class AppDelegate: UIResponder, UIApplicationDelegate {
 
     func application(_ application: UIApplication,
                      willFinishLaunchingWithOptions launchOptions: [UIApplication.LaunchOptionsKey: Any]?) -> Bool {
-
-        if let appLogFilePath = FileManager.appLogFileURL?.path {
-            if !Logger.configure(withFilePath: appLogFilePath) {
-                os_log("Can't open log file for writing. Log is not saved to file.", log: OSLog.default, type: .error)
-            }
-        } else {
-            os_log("Can't obtain log file URL. Log is not saved to file.", log: OSLog.default, type: .error)
-        }
-
-        wg_log(.info, message: "Launching app")
-        wg_log_versions_to_file()
+        Logger.configureGlobal(withFilePath: FileManager.appLogFileURL?.path, withTag: "APP")
 
         let window = UIWindow(frame: UIScreen.main.bounds)
         window.backgroundColor = UIColor.white