Rename media constraints model and store.

webrtc/examples/objc/AppRTCMobile/ios/ARDMediaConstraintsSettingsStore.m

-/*
- *  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 "ARDMediaConstraintsSettingsStore.h"
-
-static NSString *const kUserDefaultsMediaConstraintsKey =
-    @"rtc_video_resolution_media_constraints_key";
-
-NS_ASSUME_NONNULL_BEGIN
-@implementation ARDMediaConstraintsSettingsStore
-
-- (nullable NSString *)videoResolutionConstraintsSetting {
-  return [[NSUserDefaults standardUserDefaults] objectForKey:kUserDefaultsMediaConstraintsKey];
-}
-
-- (void)setVideoResolutionConstraintsSetting:(NSString *)constraintsString {
-  [[NSUserDefaults standardUserDefaults] setObject:constraintsString
-                                            forKey:kUserDefaultsMediaConstraintsKey];
-}
-
-@end
-NS_ASSUME_NONNULL_END