iOS Swift Conversion (#2527)

Converts iOS implementation from Objective-c to Swift

# During the conversion process some updates to the code structure were also made
- Modularize codebase from single file to smaller focused files
- Untangled large nested IF statements
- Added more null checks, since Swift is more strict with null pointers
- Added property to allow for decoding of local video sources with self contained key for offline playback
- Updates example apps to test react-native 0.63.4 and uses auto native dependency imports for android and ios

ios/Video/DataStructures/DRMParams.swift

@@ -0,0 +1,30 @@
+struct DRMParams {
+    let type: String?
+    let licenseServer: String?
+    let headers: Dictionary<String,Any>?
+    let contentId: String?
+    let certificateUrl: String?
+    let base64Certificate: Bool?
+    
+    let json: NSDictionary?
+    
+    init(_ json: NSDictionary!) {
+        guard json != nil else {
+            self.json = nil
+            self.type = nil
+            self.licenseServer = nil
+            self.contentId = nil
+            self.certificateUrl = nil
+            self.base64Certificate = nil
+            self.headers = nil
+            return
+        }
+        self.json = json
+        self.type = json["type"] as? String
+        self.licenseServer = json["licenseServer"] as? String
+        self.contentId = json["contentId"] as? String
+        self.certificateUrl = json["certificateUrl"] as? String
+        self.base64Certificate = json["base64Certificate"] as? Bool
+        self.headers = json["headers"] as? Dictionary<String,Any>
+    }
+}