[openFATE 309085] WEBUI: Support for adding a remote OBS instance

Feature changed by: Adrian Schröter (adrianSuSE) Feature #309085, revision 2 Title: WEBUI: Support for adding a remote OBS instance - Buildservice: Candidate + Buildservice: Done Priority Requester: Important Projectmanager: Important Requested by: Adrian Schröter (adriansuse) Developer: (Novell) Description: Add option to re-use a remote OBS instance. Should offer https://api.opensuse.org/public by default. -- openSUSE Feature: https://features.opensuse.org/309085