Background execution (#100)

* #99 Implement background tasks

* #99 Add changelog

* #99 Fix some code smells

* #99 Use background tasks in room timeline controller

* #99 Move background task service into room proxy and media provider

ElementX/Sources/Services/Background/ApplicationProtocol.swift

@@ -0,0 +1,24 @@
+//
+//  ApplicationProtocol.swift
+//  ElementX
+//
+//  Created by Ismail on 28.06.2022.
+//  Copyright © 2022 Element. All rights reserved.
+//
+
+import Foundation
+import UIKit
+
+protocol ApplicationProtocol {
+    func beginBackgroundTask(expirationHandler handler: (() -> Void)?) -> UIBackgroundTaskIdentifier
+
+    func beginBackgroundTask(withName taskName: String?, expirationHandler handler: (() -> Void)?) -> UIBackgroundTaskIdentifier
+
+    func endBackgroundTask(_ identifier: UIBackgroundTaskIdentifier)
+
+    var backgroundTimeRemaining: TimeInterval { get }
+
+    var applicationState: UIApplication.State { get }
+}
+
+extension UIApplication: ApplicationProtocol {}