chore: add custom titles, description and chapters

ios/Video/DataStructures/Chapter.swift

@@ -0,0 +1,25 @@
+
+struct Chapter {
+    let title: String
+    let uri: String
+    let startTime: Double
+    let endTime: Double
+    
+    let json: NSDictionary?
+    
+    init(_ json: NSDictionary!) {
+        guard json != nil else {
+            self.json = nil
+            self.title = ""
+            self.uri = ""
+            self.startTime = 0
+            self.endTime = 0
+            return
+        }
+        self.json = json
+        self.title = json["title"] as? String ?? ""
+        self.uri = json["uri"] as? String ?? ""
+        self.startTime = json["startTime"] as? Double ?? 0
+        self.endTime = json["endTime"] as? Double ?? 0
+    }
+}