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/RCTSwiftLog/RCTSwiftLog.swift

@@ -0,0 +1,53 @@
+//
+//  RCTLog.swift
+//  WebViewExample
+//
+//  Created by Jimmy Dee on 4/5/17.
+//  Copyright © 2017 Branch Metrics. All rights reserved.
+//
+
+/*
+ * Under at least some conditions, output from NSLog has been unavailable in the RNBranch module.
+ * Hence that module uses the RCTLog macros from <React/RCTLog.h>. The React logger is nicer than
+ * NSLog anyway, since it provides log levels with runtime filtering, file and line context and
+ * an identifier for the thread that logged the message.
+ *
+ * This wrapper lets you use functions with the same name in Swift. For example:
+ *
+ * RCTLogInfo("application launched")
+ *
+ * generates
+ *
+ * 2017-04-06 12:31:09.611 [info][tid:main][AppDelegate.swift:18] application launched
+ *
+ * This is currently part of this sample app. There may be some issues integrating it into an
+ * Objective-C library, either react-native-branch or react-native itself, but it may find its
+ * way into one or the other eventually. Feel free to reuse it as desired.
+ */
+
+func RCTLogError(_ message: String, _ file: String=#file, _ line: UInt=#line) {
+    RCTSwiftLog.error(message, file: file, line: line)
+}
+
+func RCTLogWarn(_ message: String, _ file: String=#file, _ line: UInt=#line) {
+    RCTSwiftLog.warn(message, file: file, line: line)
+}
+
+func RCTLogInfo(_ message: String, _ file: String=#file, _ line: UInt=#line) {
+    RCTSwiftLog.info(message, file: file, line: line)
+}
+
+func RCTLog(_ message: String, _ file: String=#file, _ line: UInt=#line) {
+    RCTSwiftLog.log(message, file: file, line: line)
+}
+
+func RCTLogTrace(_ message: String, _ file: String=#file, _ line: UInt=#line) {
+    RCTSwiftLog.trace(message, file: file, line: line)
+}
+
+func DebugLog(_ message: String) {
+#if DEBUG
+    print(message)
+#endif
+}
+