Document Provider Flags

[luebken]

What problem are you facing?

I'm trying to explore the behavior of this provider. This could be pure exploratory or in some troubleshooting use-case.

How could Crossplane help solve your problem?

https://github.com/crossplane/provider-gcp/blob/master/cmd/provider/main.go#L36 lists a couple of flags that are useful: debug, sync, poll, leader-election. These should be documented and how us user can set them. e.g. with ControllerConfig

See also crossplane-contrib/provider-aws#808