Added edge case to error handling on base classes and SFU pipeline cleanup on room empty

labs/bbb-webrtc-sfu/lib/base/BaseManager.js

labs/bbb-webrtc-sfu/lib/base/BaseProvider.js

...b-webrtc-sfu/lib/mcs-core/lib/adapters/kurento/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/MediaSession.js

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