Add more production readiness doc

[linsun]

This is discovered during DD when comparing with other project like Istio.

Some examples I provided: Let me send an example from Istio which is a graduated project
3:47
https://istio.io/latest/docs/ops/ & https://istio.io/latest/docs/ops/best-practices/

@evankanderson mentioned he will file a CNCF service desk to get some help. Please update the issue as needed if resolved!