feat(iOS) expose activating/deactivating audio session functionality

ios/sdk/sdk.xcodeproj/project.pbxproj

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+		4ED4FFF12721B9B90074E620 /* JitsiAudioSession.h */ = {isa = PBXFileReference; lastKnownFileType = sourcecode.c.h; path = JitsiAudioSession.h; sourceTree = "<group>"; };
+		4ED4FFF22721B9B90074E620 /* JitsiAudioSession.m */ = {isa = PBXFileReference; lastKnownFileType = sourcecode.c.objc; path = JitsiAudioSession.m; sourceTree = "<group>"; };
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 				DEFE535821FB311F00011A3A /* JitsiMeet+Private.h */,
 				DEA9F283258A5D9900D4CD74 /* JitsiMeetSDK.h */,
 				DEFE535321FB1BF800011A3A /* JitsiMeet.m */,
+				4ED4FFF12721B9B90074E620 /* JitsiAudioSession.h */,
+				4ED4FFF52721BAE10074E620 /* JitsiAudioSession+Private.h */,
+				4ED4FFF22721B9B90074E620 /* JitsiAudioSession.m */,
 				DEAD3224220C497000E93636 /* JitsiMeetConferenceOptions.h */,
 				DEAD3228220C734300E93636 /* JitsiMeetConferenceOptions+Private.h */,
 				DEAD3225220C497000E93636 /* JitsiMeetConferenceOptions.m */,
 				4E51B76425E5345E0038575A /* ScheenshareEventEmiter.h in Headers */,
 				DE65AACC2318028300290BEC /* JitsiMeetBaseLogHandler+Private.h in Headers */,
 				0B412F221EDEF6EA00B1A0A6 /* JitsiMeetViewDelegate.h in Headers */,
+				4ED4FFF32721B9B90074E620 /* JitsiAudioSession.h in Headers */,
 				0BD906EA1EC0C00300C8C18E /* JitsiMeet.h in Headers */,
 				DE81A2D42316AC4D00AE1940 /* JitsiMeetLogger.h in Headers */,
 				DE65AACA2317FFCD00290BEC /* LogUtils.h in Headers */,
 			files = (
 				0BB9AD7B1F5EC8F4001C08DB /* CallKit.m in Sources */,
 				DE81A2DF2317ED5400AE1940 /* JitsiMeetBaseLogHandler.m in Sources */,
+				4ED4FFF42721B9B90074E620 /* JitsiAudioSession.m in Sources */,
 				0BB9AD7D1F60356D001C08DB /* AppInfo.m in Sources */,
 				DE81A2D92316AC7600AE1940 /* LogBridge.m in Sources */,
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ios/sdk/src/AudioMode.m

 #import <React/RCTLog.h>
 #import <WebRTC/WebRTC.h>
 
+#import "JitsiAudioSession+Private.h"
 #import "LogUtils.h"
 
 
         isSpeakerOn = NO;
         isEarpieceOn = NO;
 
-        RTCAudioSession *session = [RTCAudioSession sharedInstance];
+        RTCAudioSession *session = JitsiAudioSession.rtcAudioSession;
         [session addDelegate:self];
     }
 
 
 - (BOOL)setConfigWithoutLock:(RTCAudioSessionConfiguration *)config
                        error:(NSError * _Nullable *)outError {
-    RTCAudioSession *session = [RTCAudioSession sharedInstance];
+    RTCAudioSession *session = JitsiAudioSession.rtcAudioSession;
 
     return [session setConfiguration:config error:outError];
 }
 - (BOOL)setConfig:(RTCAudioSessionConfiguration *)config
             error:(NSError * _Nullable *)outError {
 
-    RTCAudioSession *session = [RTCAudioSession sharedInstance];
+    RTCAudioSession *session = JitsiAudioSession.rtcAudioSession;
     [session lockForConfiguration];
     BOOL success = [self setConfigWithoutLock:config error:outError];
     [session unlockForConfiguration];
                   reject:(RCTPromiseRejectBlock)reject) {
     DDLogInfo(@"[AudioMode] Selected device: %@", device);
     
-    RTCAudioSession *session = [RTCAudioSession sharedInstance];
+    RTCAudioSession *session = JitsiAudioSession.rtcAudioSession;
     [session lockForConfiguration];
     BOOL success;
     NSError *error = nil;
             RTCAudioSessionConfiguration *config = [self configForMode:self->activeMode];
             [self setConfig:config error:nil];
             if (self->forceSpeaker && !self->isSpeakerOn) {
-                RTCAudioSession *session = [RTCAudioSession sharedInstance];
+                RTCAudioSession *session = JitsiAudioSession.rtcAudioSession;
                 [session lockForConfiguration];
                 [session overrideOutputAudioPort:AVAudioSessionPortOverrideSpeaker error:nil];
                 [session unlockForConfiguration];

ios/sdk/src/JitsiAudioSession+Private.h

+/*
+ * Copyright @ 2017-present 8x8, Inc.
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *     http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+#import "JitsiAudioSession.h"
+
+@interface JitsiAudioSession (Private)
+
++ (RTCAudioSession *)rtcAudioSession;
+
+@end

ios/sdk/src/JitsiAudioSession.h

+/*
+ * Copyright @ 2017-present 8x8, Inc.
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *     http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+#import <Foundation/Foundation.h>
+
+@class AVAudioSession;
+
+@interface JitsiAudioSession : NSObject
+
++ (void)activateWithAudioSession:(AVAudioSession *)session;
++ (void)deactivateWithAudioSession:(AVAudioSession *)session;
+
+@end

ios/sdk/src/JitsiAudioSession.m

+/*
+ * Copyright @ 2017-present 8x8, Inc.
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *     http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+#import "JitsiAudioSession.h"
+#import "JitsiAudioSession+Private.h"
+#import <WebRTC/WebRTC.h>
+
+@implementation JitsiAudioSession
+
++ (RTCAudioSession *)rtcAudioSession {
+    return [RTCAudioSession sharedInstance];
+}
+
++ (void)activateWithAudioSession:(AVAudioSession *)session {
+    [self.rtcAudioSession audioSessionDidActivate:session];
+}
+
++ (void)deactivateWithAudioSession:(AVAudioSession *)session {
+    [self.rtcAudioSession audioSessionDidDeactivate:session];
+}
+
+@end

ios/sdk/src/JitsiMeetSDK.h

 #import <JitsiMeetSDK/JitsiMeetConferenceOptions.h>
 #import <JitsiMeetSDK/JitsiMeetLogger.h>
 #import <JitsiMeetSDK/JitsiMeetBaseLogHandler.h>
+#import <JitsiMeetSDK/JitsiAudioSession.h>
 #import <JitsiMeetSDK/InfoPlistUtil.h>

ios/sdk/src/callkit/CallKit.m

 #import <JitsiMeetSDK/JitsiMeetSDK-Swift.h>
 
 #import "../LogUtils.h"
+#import "JitsiAudioSession.h"
 
 
 // The events emitted/supported by RNCallKit:
 - (void) providerDidActivateAudioSessionWithSession:(AVAudioSession *)session {
     DDLogInfo(@"[RNCallKit][CXProviderDelegate][provider:didActivateAudioSession:]");
 
-    [[RTCAudioSession sharedInstance] audioSessionDidActivate:session];
+    [JitsiAudioSession activateWithAudioSession:session];
 }
 
 - (void) providerDidDeactivateAudioSessionWithSession:(AVAudioSession *)session {
     DDLogInfo(@"[RNCallKit][CXProviderDelegate][provider:didDeactivateAudioSession:]");
 
-    [[RTCAudioSession sharedInstance] audioSessionDidDeactivate:session];
+    [JitsiAudioSession deactivateWithAudioSession:session];
 }
 
 - (void) providerTimedOutPerformingActionWithAction:(CXAction *)action {