[New: openFATE 310134] Support product signing with non local builds

Feature added by: Adrian Schröter (adrianSuSE) Feature #310134, revision 1 Title: Support product signing with non local builds Buildservice: Evaluation Priority Requester: Important Projectmanager: Important Requested by: Adrian Schröter (adriansuse) Developer: (Novell) Description: Signing of product images is only working when a local worker is used. The feature is to support this also on usual workers. -- openSUSE Feature: https://features.opensuse.org/310134