Add a metric to count the number of rollout restarts

[mnacharov]

Is your feature request related to a problem? Please describe.
To monitor and alert on conditions like the recent #1126, it would be great to count each restart.

Describe the solution you'd like
Add a metric such as vso_rollout_restarts_total and count for each target, like that:

vso_rollout_restarts_total{namespace="default", name="my-secret", target_name="my-workload", target_kind="Deployment"} 1

Describe alternatives you've considered
I haven't found any metric which showed such statistics. Sure, I have kube-state-metrics, which shows this anomaly, but this way I could find the reason faster.

Additional context