[FEATURES]log printing should has an standard

[yangyuliufeng]

What feature you'd like to add: In the fluid Project, we use the logger interface from github.com/go-logr/logr/logr.go to print log. When sewing a logger, we pass some key-value parameters so that the log will contain them. However, what key-value parameters should be printed in the log, there is no specification.

Why is this feature needed: We should make a standard about when to print to warn or info log, and what information should be given in the log. The standard should be shown in the doc to help the developer.