Multi file uploads (#4358)

* Allow MediaPickerScreen users to select the media selection mode (single or multiple)

* Fix cancellation

* Add support for multiple media URLs on the MediaUploadPreviewScreen.

* Support processing more URLs on the `MediaUploadingPreprocessor` and sending more on the `MediaUploadPreviewScreen`

* Add feature flag for `multipleAttachmentUploadEnabled`

* Add a label showing the current preview item index in the MediaUploadPreviewScreen

* Add support for dragging and dropping or pasting multiple items at the same time.

* Support sharing more than one file through the share extension.

* Limit the number of items that can be shared in one go to 5.

* Fix unit tests

* Fix incorrect fatal error when dealing with single selection media pickers.

* Document the `multipleAttachmentUploadEnabled` usage in the context of the MediaPicker.

* Use a task group for processing selected media in the photo library picker.

* Use a task group for processing multiple selected media in the MediaUploadingPreprocessor

* Switch the maximum number of items that can be shared to 10.

* Allow multiple items to be pasted at the same time.

ElementX/Sources/Screens/Settings/DeveloperOptionsScreen/DeveloperOptionsScreenModels.swift

@@ -38,15 +38,19 @@ enum DeveloperOptionsScreenViewAction {
 protocol DeveloperOptionsProtocol: AnyObject {
     var logLevel: LogLevel { get set }
     var traceLogPacks: Set<TraceLogPack> { get set }
-    var publicSearchEnabled: Bool { get set }
-    var hideUnreadMessagesBadge: Bool { get set }
-    var fuzzyRoomListSearchEnabled: Bool { get set }
+    
     var enableOnlySignedDeviceIsolationMode: Bool { get set }
     var enableKeyShareOnInvite: Bool { get set }
-    var elementCallBaseURLOverride: URL? { get set }
-    var knockingEnabled: Bool { get set }
     var threadsEnabled: Bool { get set }
     var hideQuietNotificationAlerts: Bool { get set }
+    var multipleAttachmentUploadEnabled: Bool { get set }
+    
+    var hideUnreadMessagesBadge: Bool { get set }
+    var elementCallBaseURLOverride: URL? { get set }
+    
+    var publicSearchEnabled: Bool { get set }
+    var fuzzyRoomListSearchEnabled: Bool { get set }
+    var knockingEnabled: Bool { get set }
     var sharePosEnabled: Bool { get set }
 }
 

ElementX/Sources/Screens/Settings/DeveloperOptionsScreen/View/DeveloperOptionsScreen.swift

@@ -52,6 +52,12 @@ struct DeveloperOptionsScreen: View {
                 }
             }
             
+            Section("Timeline") {
+                Toggle(isOn: $context.multipleAttachmentUploadEnabled) {
+                    Text("Allow selecting multiple attachments for upload")
+                }
+            }
+            
             Section("Join rules") {
                 Toggle(isOn: $context.knockingEnabled) {
                     Text("Knocking")