Pass settings model to ARDAppClient instead of individual settings.

webrtc/examples/objc/AppRTCMobile/ios/ARDSettingsStore.h

-/*
- *  Copyright 2016 The WebRTC Project Authors. All rights reserved.
- *
- *  Use of this source code is governed by a BSD-style license
- *  that can be found in the LICENSE file in the root of the source
- *  tree. An additional intellectual property rights grant can be found
- *  in the file PATENTS.  All contributing project authors may
- *  be found in the AUTHORS file in the root of the source tree.
- */
-
-#import <Foundation/Foundation.h>
-
-NS_ASSUME_NONNULL_BEGIN
-
-/**
- * Light-weight persistent store for user settings.
- *
- * It will persist between application launches and application updates.
- */
-@interface ARDSettingsStore : NSObject
-
-@property(nonatomic) NSString* videoCodec;
-
-/**
- * Returns current video resolution media constraint string stored in the store.
- */
-- (nullable NSString *)videoResolutionConstraints;
-
-/**
- * Stores the provided value as video resolution media constraint.
- * @param value the string to be stored
- */
-- (void)setVideoResolutionConstraints:(NSString *)value;
-
-/**
- * Returns current max bitrate number stored in the store.
- */
-- (nullable NSNumber *)maxBitrate;
-
-/**
- * Stores the provided value as maximum bitrate setting.
- * @param value the number to be stored
- */
-- (void)setMaxBitrate:(nullable NSNumber *)value;
-
-@end
-NS_ASSUME_NONNULL_END