Re: [sr-dev] [kamailio/kamailio] Lost selectors (#2705)

according to the latest version of NENA i3, the Call-Info header purpose changes from nena-xxx to emergency-xxx (e.g. nena-IncidentId will be replaced by emergency-IncidentId); perhaps this can already be taken into account.

Think we need a write a function to convert headers to required format like ``` cast_nena_headers_prefix("nena-"); cast_nena_headers_prefix("emergency-"); ```

do we need a new release every time new selectors are needed? For instance in Europe we can have purpose=EmergencyCallData.eCall.MSD when NG eCall is rolled out.

RFC documents not changed rarely. I think we can add a selector for this RFC also like ``` @lost.emergency_call_data.ecall_msd; ```