NethVoice: create a general parameter for deleting call recordings and data

[andrea-marchionni]

• it is necessary to establish how long to keep the call recordings

• it is necessary to establish how long to keep the historical call data for both the CDR report and the code report

• it is necessary to establish how long to keep the voicemail file

Evaluate whether to expose the configuration of these parameters in the interface (module or NethVoice?) or leave them in the environment