Move DB updates for updating conference status from VI to Conference

[maria-farooq]

VoiceInterpreter is updating DB status of conference whenever it receives ConferenceStateChanged msg. These calls should be in Conference Actor which is originating ConferenceStateChanged message.

• https://github.com/RestComm/Restcomm-Connect/blob/master/restcomm/restcomm.interpreter/src/main/java/org/mobicents/servlet/restcomm/interpreter/VoiceInterpreter.java#L2539
• https://github.com/RestComm/Restcomm-Connect/blob/master/restcomm/restcomm.interpreter/src/main/java/org/mobicents/servlet/restcomm/interpreter/VoiceInterpreter.java#L2615

[maria-farooq]

merged inside #1104