Research the possibility of integration with a service mesh provider

[osdrv]

Currently Shipper traffic shifting is entirely based upon the internal k8s mechanisms of label selectors and label shifting. This makes it quite imprecise in terms of traffic share management. For example, if an incumbent holds 2 active pods and a contender activates 1 more, traffic weight manifest claiming weights 100 for incumbent and 1 for contender will effectively route 2/3 of the traffic to incumbent and 1/3 to contender. This might be an extremely dangerous scenario for mission critical workloads.

This ticket is created for the purpose of collecting some ideas around using service mesh providers (e.g. https://istio.io/) as a traffic shifting mechanism. An example of an architecture flexible to multiple service mesh providers: https://github.com/weaveworks/flagger.