Allow to set a CredentialsProvider on relevant API commands This is needed for commands that use Transport internally. Change-Id: I9417c85255b160723968c647063b9c7e05995ea4 Signed-off-by: Mathias Kinzler <mathias.kinzler@sap.com> Signed-off-by: Chris Aniszczyk <caniszczyk@gmail.com>