Added Audio support to SFU and a new Freeswitch adapter

labs/bbb-webrtc-sfu/lib/ProcessManager.js

labs/bbb-webrtc-sfu/lib/audio/AudioManager.js

labs/bbb-webrtc-sfu/lib/audio/AudioProcess.js

labs/bbb-webrtc-sfu/lib/audio/audio.js

...bb-webrtc-sfu/lib/connection-manager/ConnectionManager.js

...-sfu/lib/mcs-core/lib/adapters/freeswitch/AudioHandler.js

...tc-sfu/lib/mcs-core/lib/adapters/freeswitch/freeswitch.js

labs/bbb-webrtc-sfu/lib/mcs-core/lib/adapters/kurento.js

labs/bbb-webrtc-sfu/lib/mcs-core/lib/constants/Constants.js

.../bbb-webrtc-sfu/lib/mcs-core/lib/media/MediaController.js

labs/bbb-webrtc-sfu/lib/mcs-core/lib/model/SdpSession.js

labs/bbb-webrtc-sfu/lib/mcs-core/lib/model/SfuUser.js

labs/bbb-webrtc-sfu/lib/mcs-core/lib/model/UriSession.js

labs/bbb-webrtc-sfu/lib/mcs-core/lib/utils/util.js

labs/bbb-webrtc-sfu/package-lock.json

labs/bbb-webrtc-sfu/package.json