Adopt consolidated logging mechanism (#4370)

* Adopted the new MXLog and replaced NSLog throughout the application - vector-im/element-ios/issues/4351
* Replaced NSLog() and print() usages with MXLog.debug()
* Added swiftlint rules for NSLog(), print(), println() and os_log()
* Escape paths used to run script build phases for swiftlint and swiftgen

Riot/Modules/KeyBackup/Recover/RecoveryKey/KeyBackupRecoverFromRecoveryKeyViewController.swift

@@ -215,7 +215,7 @@ final class KeyBackupRecoverFromRecoveryKeyViewController: UIViewController {
         do {
             documentContent = try String(contentsOf: documentURL)
         } catch {
-            print("Error: \(error)")
+            MXLog.debug("Error: \(error)")
             documentContent = nil
         }