manage the Fritz!Box phonebook from Perl

Changes for 0.07 - 2023-07-25

• . All changes contributed by Andreas Voegele . Fix PhonebookEntry->save() to call 'SetPhonebookEntry' instead of the non-existing 'AddPhonebookEntry' . Updated links to AVM documentation . Fix usage of Test::isn't (now Test::isnt()) . Appveyor fixes