Add istio-cni to synker file

Istio CNI should be part of synker file since its part of the Istio deployment.

Related: #492 (closed) #726 (closed) #710 (closed)

mentioned in merge request !846 (merged)

mentioned in merge request !853 (merged)

mentioned in merge request !854 (merged)

closed with merge request !854 (merged)

mentioned in commit 38f60ac1