Adds “Disable Response Caching” debug setting

When enabled, AltStore will ignore cached responses for certain requests and will always make a new request to the server. This is useful for development when repeatedly testing changes to remote files.

Limited to UpdateKnownSourcesOperation for now, but will eventually affect fetching sources as well.

AltStore/Settings/SettingsViewController.swift

@@ -53,6 +53,7 @@ extension SettingsViewController
     {
         case sendFeedback
         case refreshAttempts
+        case responseCaching
     }
 }
 
@@ -71,6 +72,7 @@ class SettingsViewController: UITableViewController
     
     @IBOutlet private var backgroundRefreshSwitch: UISwitch!
     @IBOutlet private var enforceThreeAppLimitSwitch: UISwitch!
+    @IBOutlet private var disableResponseCachingSwitch: UISwitch!
     
     @IBOutlet private var versionLabel: UILabel!
     
@@ -159,6 +161,7 @@ private extension SettingsViewController
         
         self.backgroundRefreshSwitch.isOn = UserDefaults.standard.isBackgroundRefreshEnabled
         self.enforceThreeAppLimitSwitch.isOn = !UserDefaults.standard.ignoreActiveAppsLimit
+        self.disableResponseCachingSwitch.isOn = UserDefaults.standard.responseCachingDisabled
         
         if self.isViewLoaded
         {
@@ -331,6 +334,11 @@ private extension SettingsViewController
         }
     }
     
+    @IBAction func toggleDisableResponseCaching(_ sender: UISwitch)
+    {
+        UserDefaults.standard.responseCachingDisabled = sender.isOn
+    }
+    
     @IBAction func addRefreshAppsShortcut()
     {
         guard let shortcut = INShortcut(intent: INInteraction.refreshAllApps().intent) else { return }
@@ -591,7 +599,7 @@ extension SettingsViewController
                     toastView.show(in: self)
                 }
                 
-            case .refreshAttempts: break
+            case .refreshAttempts, .responseCaching: break
             }
             
         case .account, .patreon, .instructions, .macDirtyCow: break