support istio fault-injection

[S-mishina]

Describe the feature

Currently, fault-injection cannot be implemented without delegating the failure test. We would like to implement fault-injection functionality in the flagger.

ref: link

Proposed solution

Implement canary.service.fault.

Any alternatives you've considered?

I can't think of anything in particular.

[S-mishina]

If it is not a problem, I would like to work on my end.