[Reviewer: Andy] Call Diversion AS

Alex,

Please can you review the call diversion AS code?  I've manually live-tested but not yet UT-ed (except for simservs, which was trivial) or regressibly-live-tested.

Matt
Is this a bad precedent to set?  In future I can see us wanting to do the same trick again with privacy or call barring.  Would we have a selection of orthogonal constructors?

Is it nicer to have an empty constructor and add functions to enable a given IR.92 service (with that services parameters)?