[Rest] Use-cases for ACH

[Shida Schubert]

All;

  Below are some use-cases Markus presented.. I have also looked at
the services we provide in Japan and jotted down those that are
configured on the proxy by pressing a sequence of button or by selecting
an option on the phone.

* Call forwarding unconditional: either to voicemail or to any other  
number.
* Call forwarding on busy: either to voicemail or to any other number.
* Call forwarding on no answer: either to voicemail or to any other  
number.
* Call forwarding when not registered: either to voicemail or to any  
other number.
* Call forwarding when not reachable: either to voicemail or to any  
other number.

* Barring on all outgoing calls: on/off
* Barring on all outgoing international calls: on/off
* Barring on all outgoing calls when roaming except to own service  
provider: on/off
* Barring on all incoming calls: on/off
* Barring on all incoming calls when roaming: on/off

1. Enabling anonymous call reject.
    > Enabling the ability to reject call when call is anonymous.
2. Enabling call-waiting
3. Enabling voicemail (This is probably equal to the forwarding Markus  
presented)
4. Enabling DND

  Regards
   Shida