iOS - add APIs & doc

1.增加 API - addDismissActions
2.增加 API - addNotificationActions
3.增加封装类 NotificationService
4.更新对应文档

src/ios/notificationService/NotificationService.m

@@ -0,0 +1,44 @@
+//
+//  NotificationService.m
+//  jpushNotificationService
+//
+//  Created by wuxingchen on 16/10/10.
+//
+//
+
+#import "NotificationService.h"
+#import <UIKit/UIKit.h>
+
+@interface NotificationService ()
+
+@property (nonatomic, strong) void (^contentHandler)(UNNotificationContent *contentToDeliver);
+@property (nonatomic, strong) UNMutableNotificationContent *bestAttemptContent;
+
+@end
+
+@implementation NotificationService
+
+- (void)didReceiveNotificationRequest:(UNNotificationRequest *)request withContentHandler:(void (^)(UNNotificationContent * _Nonnull))contentHandler {
+
+    self.contentHandler = contentHandler;
+    self.bestAttemptContent = [request.content mutableCopy];
+
+    @try {
+        NSString *urlStr = [request.content.userInfo valueForKey:@"JPushPluginAttachment"];
+        NSArray *urls = [urlStr componentsSeparatedByString:@"."];
+        NSURL *urlNative = [[NSBundle mainBundle] URLForResource:urls[0] withExtension:urls[1]];
+        UNNotificationAttachment *attachment = [UNNotificationAttachment attachmentWithIdentifier:urlStr URL:urlNative options:nil error:nil];
+        self.bestAttemptContent.attachments = @[attachment];
+    } @catch (NSException *exception) {
+    }
+
+    self.contentHandler(self.bestAttemptContent);
+}
+
+- (void)serviceExtensionTimeWillExpire {
+    // Called just before the extension will be terminated by the system.
+    // Use this as an opportunity to deliver your "best attempt" at modified content, otherwise the original push payload will be used.
+    self.contentHandler(self.bestAttemptContent);
+}
+
+@end