Support Voicemail natively

[soroshsabz]

ITNOA

Is your feature request related to a problem? Please describe. This feature request is aimed at accessing the events published by freeswitch regarding it's VoiceMail functionality.

Describe the solution you'd like Natively supporting Event Headers and Messages in a structured way pertaining to Voice mail module of freeswitch.

Describe alternatives you've considered while these events can be manually parsed as any other custom event at a higher layer, It is preferable to Implement the parsing of these events data alongside other custom events to prevent code duplication and move logic closer to data.