add module func_key_dest_service
fix indentation
remove ressources handled by new style func-keys from old get_phonefunckey
remove useless function key option (enablevmbox)
add service func_key in user application
add missing break in switch
add extensions module in func_key manager
add func_key destination service  to func_key manager

needed to adapt extensions and func_key objects to deal with the fact
that foreign key of table func_key_dest_service is not service_id but
extension_id (all previous cases took for granted that table
func_key_dest_DESTINATION would have a foreign key DESTINATION_id)
fix arguments passed to get_fk_id_with_dst since signature changed
add internal validation to avoid chaos and mayhem
add even more internal validation to avoid chaos and mayhem
restrict service function keys to be handled by new-style func-keys

only voicemail function keys are currently supported. All other service
function keys are still handled within phonefunckey.
extract logic for generating extenfeature func keys
generate correct extensions in new func key system
Merge branch '5022-func-dest-extension-rebased'